ALTM Arcadium Lithium plc

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4.Includes the Company's $39.1 million cash contributed to Nemaska Lithium in the first quarter of 2024 which, due to quarter-lag reporting, is not yet recorded in our consolidation of Nemaska. The balance is recorded to Other assets - noncurrent because the cash is expected to be used by Nemaska primarily for capital expenditures. See Note 9 for details.

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Background and Nature of Operations

Arcadium Lithium plc ("Arcadium", "Arcadium Lithium", "we", "us", "Company" or "our") is a public limited company incorporated under the laws of the Bailiwick of Jersey. On January 4, 2024, Arcadium Lithium completed the previously announced Allkem Livent Merger by which Livent Corporation, a Delaware corporation ("Livent"), and Allkem Limited, an Australian company limited by shares ("Allkem"), became wholly owned subsidiaries of Arcadium Lithium. On January 4, 2024, the Company's shares started trading on the New York Stock Exchange under the trading symbol ALTM. See Note 4, Allkem Livent Merger for further details.

While Arcadium Lithium is a newly formed company from the merger of Allkem and Livent, our company has a rich heritage of innovation and a long, proven history of producing performance lithium compounds in a safe and sustainable manner. We are vertically integrated, with a global footprint and industry-leading end-to-end capabilities across lithium production including hard-rock mining, conventional pond-based brine extraction, direct lithium brine extraction and lithium chemicals manufacturing.

Our lithium asset portfolio, consisting of both operating assets and development projects, provides us with global reach, scale, and product flexibility. Today we have operating resources in Argentina and Australia and downstream conversion assets in the U.S., China, Japan, and the U.K. We also have multiple ongoing development projects in Argentina (greenfield and brownfield) and Canada (greenfield) to increase production capabilities and our ability to meet the needs of customers around the world. In the U.S., we operate the only integrated mine-to-metal production facility in the Western Hemisphere for high purity lithium metal, a core component of next generation battery technologies.

In this Form 10-Q, the results of the Company as of and for the three months ended March 31, 2024 include the operations and financial position of Allkem. Because Arcadium Lithium plc is the successor company to Livent in the Allkem Livent Merger, we are presenting the results of predecessor Livent’s operations for the three months ended March 31, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. Refer to Note 4 for further information related to the Allkem Livent Merger.

The accompanying condensed consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission ("SEC") for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. GAAP have been condensed or omitted from these interim financial statements. The financial statements included in this report reflect all normal and recurring adjustments which, in the opinion of management, are necessary for a fair presentation of our condensed consolidated balance sheets as of March 31, 2024 and December 31, 2023, the condensed consolidated results of operations, the condensed consolidated statement of comprehensive income and the condensed consolidated statement of changes in equity for the three months ended March 31, 2024 and 2023, and the condensed consolidated cash flows for the three months ended March 31, 2024 and 2023. All intercompany transactions and balances have been eliminated in consolidation. For entities that we control, but own less than 100%, we record the minority ownership as noncontrolling interest. The unaudited results of operations for the interim periods reported are not necessarily indicative of results to be expected for the full year. These statements, therefore, should be read in conjunction with the annual consolidated financial statements and related notes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (the "2023 Annual Report on Form 10-K").

Segment Information

In January 2024, Arcadium Lithium completed the Allkem Livent Merger. See Note 4, Allkem Livent Merger for further details. Following the closing of the Allkem Livent Merger, we currently operate as one reportable segment based on the commonalities among our products and services. As integration evolves, we will continue to assess this determination.

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Revenue Recognition

Revenue from product sales is recognized when we satisfy a performance obligation by transferring the promised goods to a customer, that is, when control of the good transfers to the customer. Payment terms generally range from 20 to 180 days.

In determining when the control of goods is transferred, we typically assess, among other things, the transfer of title and risk of loss and the shipping terms of the contract.

We record amounts billed for shipping and handling fees as revenue. Costs incurred for shipping and handling are recorded in cost of sales. When we perform shipping and handling activities after the transfer of control to the customer (e.g., when control transfers prior to delivery), they are considered fulfillment activities, and accordingly, the costs are accrued to cost of sales when the related revenue is recognized.

Amounts billed for sales and use taxes, VAT, and certain excise and other specific transactional taxes imposed on revenue-producing transactions are presented on a net basis and excluded from revenue in the condensed consolidated statements of operations. We record a liability until remitted to the respective taxing authority.

We satisfy our obligations by transferring goods and services in exchange for consideration from customers. The timing of performance sometimes differs from the timing the associated consideration is received from the customer, thus resulting in the recognition of a contract asset or liability. These may arise from provisional pricing within certain of our customer contracts, or if the customer’s payment of consideration is received prior to completion of our related performance obligation. Provisional pricing results in variable consideration which we estimate by using an expected value method taking into account all information that is reasonably available including publicly available pricing forecasts. We only include variable consideration within the transaction price to the extent that it is probable that a significant reversal in the amount of revenue recognized will not occur.

Equity method investments

We stop applying the equity method when we have reduced the value of our equity method investment, commitments and additional investments (i.e., loans or advances) in the investee to zero. If the investee subsequently reports net income, we resume applying the equity method when our share of that net income is equal to the suspended losses (i.e., our share of the investee's net losses not previously recognized).

If facts and circumstances indicate that a decrease in value of the investment has occurred that is other than temporary, we recognize an impairment loss equal to an amount by which the carrying amount exceeds the fair value of the equity method investment. There were no impairments during the three months ended March 31, 2024.

Goodwill

The Company accounts for goodwill and other intangibles acquired in a business combination in conformity with current accounting guidance that requires that goodwill and indefinite-lived intangible assets not be amortized.

Under the guidance, goodwill is tested for impairment by comparing the estimated fair value of reporting units to the related carrying value. Reporting units are either operating business segments or one level below operating business segments for which discrete financial information is available and for which operating results are regularly reviewed by the business management. In applying the goodwill impairment test, a qualitative test ("Step 0") is initially performed, under which qualitative factors are assessed to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. Qualitative factors may include, but are not limited to, economic conditions, industry and market considerations, cost factors, overall financial performance of the reporting units and other entity and reporting unit specific events. If after assessing these qualitative factors, it is determined that it is "more-likely-than-not" that the fair value of the reporting unit is less than the carrying value, a quantitative test ("Step 1") is performed. During Step 1, the fair value is estimated using a discounted cash flow model.

Mine Development Costs

Mine development costs include: a) exploration and evaluation ("E&E") expenditures incurred during the search for mineral resources as well as the determination of the technical feasibility and commercial viability of extracting the mineral resource; and b) stripping costs of removing overburden and waste materials to access the mineral body at an open pit mine.

The Company capitalizes E&E expenditures to PP&E under a successful efforts basis when proven and probable reserves are established for the sites where E&E activities are being performed. E&E assets recognized as part of business combinations are also capitalized. All other E&E expenditures are expensed.

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Stripping costs incurred prior to the production phase are capitalized to PP&E during the development of an open pit mine. When multiple open pits exist at a mining complex utilizing common processing facilities, such pre-production stripping costs are capitalized at each pit. The removal, production, and sale of de minimis saleable materials may occur during the development phase of an open pit mine and are assigned incremental mining costs related to the removal of that material. The production phase of an open pit mine commences when saleable minerals, beyond a de minimis amount, are produced. Stripping costs incurred during the production phase of a mine are variable production costs that are included as a component of inventory to be recognized in Cost of Sales in the same period as the revenue from sale of that inventory.

Capitalized mine development costs are amortized using the units-of-production method based on estimated recoverable minerals in proven and probable reserves, and are amortized over the estimated life of the mineral body.

Mineral Interests

Mineral interests include acquired interests in production, development and exploration stage properties. Mineral interests are capitalized at their fair value at the acquisition date, either as an individual asset purchase or as part of a business combination. Mineral interests in the development and exploration stage are not amortized until the underlying property is converted to the production stage, at which point the mineral interests are amortized over the estimated recoverable proven and probable reserves using a units-of-production method.

Asset Retirement Obligations

The Company accounts for asset retirement obligations ("AROs") in accordance with ASC 410-20, Asset Retirement Obligations "ASC 410-20". We record AROs at present value at the time the liability is incurred if we can reasonably estimate the settlement date. The associated AROs are capitalized as part of the carrying amount of related long-lived assets. In future periods, the liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. We also adjust the liability for changes resulting from the passage of time and/or revisions to the timing or the amount of the original estimate. Upon retirement of the long-lived asset, we either settle the obligation for its recorded amount. See Note 13, for details.

The carrying amounts of the AROs as of March 31, 2024 and December 31, 2023 was $12.5 million and $3.7 million, respectively. These amounts are included in "Accrued and other current liabilities" and "Other long-term liabilities" in our condensed consolidated balance sheets.

Blue Chip Swap

In December 2023, the Financial Accounting Standard Board ("FASB") issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU enhances existing income tax disclosures to better assess how an entity's operation and related tax risks, tax planning, and operational opportunities affect its tax rate and prospects for future cash flows.

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The ASU is effective for annual periods beginning after December 15, 2024. We are currently evaluating the effect the guidance will have on our condensed consolidated financial statements.

In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280). This ASU improves reportable segment disclosure requirements, primarily through enhanced disclosures related to significant segment expenses. The ASU is effective for annual periods beginning after December 15, 2023, and interim periods beginning after December 15, 2024. We are currently evaluating the effect the guidance will have on our condensed consolidated financial statements.

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On January 4, 2024 (the "Acquisition Date") Arcadium completed the previously announced Allkem Livent Merger by and among Livent Corporation, a Delaware corporation ("Livent"), Allkem Limited, an Australian public company ("Allkem"), Arcadium Lithium plc, a public limited company incorporated under the laws of the Bailiwick of Jersey ("Arcadium"), Lightning-A Merger Sub, Inc. ("Merger Sub"), and Arcadium Lithium Intermediate IRL Limited, a private company limited by shares and incorporated and registered in Ireland ("Irish IntermediateCo").

The transaction was consummated by way of (a) a scheme of arrangement under Australian law, pursuant to which each issued, fully paid ordinary share of Allkem held by Allkem shareholders was exchanged for either one Arcadium Lithium CHESS Depositary Instrument (a "CDI") quoted on the Australian Stock Exchange (each CDI representing a beneficial ownership interest in one Arcadium ordinary share), or one Arcadium ordinary share (par value $1.00 per share) and (b) a merger, whereby Merger Sub, a wholly owned subsidiary of Irish IntermediateCo (a direct wholly owned subsidiary of Arcadium) merged with and into Livent, with Livent as the surviving entity. Each share of Livent common stock, par value $0.001 per share (each, a "Livent Share"), was converted into the right to receive 2.406 Arcadium ordinary shares.

Pursuant to the Allkem Livent Merger, 433,156,855 Arcadium ordinary shares (including 96,909 related to accelerated PRSU awards) were issued to former Livent stockholders and 641,337,840 Arcadium ordinary shares (comprising 98,725,616 Arcadium ordinary shares and 542,612,224 CDIs in respect of Arcadium ordinary shares) were issued to former Allkem shareholders. The Acquisition Date fair value of consideration transferred consisted of the following:

(in millions)						Amount
Consideration:
Fair value of Arcadium ordinary shares issued to Allkem shareholders						$	4,385.6
Fair value of converted Allkem performance rights attributable to pre-combination service						4.8
Total consideration						$	4,390.4

The Allkem Livent Merger meets the criteria to be accounted for as a business combination and is accounted for using the acquisition method of accounting with Livent being treated as the accounting acquirer. Under the acquisition method of accounting, the assets and liabilities of Allkem and its subsidiaries are recorded at their respective fair values as of the date of completion of the Allkem Livent Merger and the difference between the fair value of the consideration paid for the acquired entity and fair value of the net assets acquired is recorded as goodwill.

The fair value of the assets, liabilities and noncontrolling interest of Allkem under the business combination guidance, including the impact of income taxes, is preliminary. The preliminary fair value allocation is subject to change for up to one year subsequent to the Acquisition Date. Determining the fair value of the assets and liabilities of Allkem requires judgement and certain assumptions to be made, the most significant of these being related to the valuation of Allkem's mining properties and rights.

Transaction and related costs directly attributable to the acquisition of Allkem, consisting primarily of advisor fees, legal fees, accounting fees, and certain deal related bonuses were $67 million, for the three months ended March 31, 2024. The costs were expensed as incurred and are included in restructuring and other charges.

The following table summarizes the preliminary purchase price allocation for the Allkem Livent Merger as of January 4, 2024, which is subject to change:

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(in Millions, except per share amounts)			Amount
Total consideration			$	4,390.4
Assets acquired:
Cash and cash equivalents			$	681.4
Trade receivables			64.2
Inventories			121.3
Prepaid and other current assets			87.2
Property, plant and equipment			4,325.5
Right of use assets - operating leases, net			53.4
Deferred income tax assets			26.3
Other assets (1)			192.9
Total assets acquired			$	5,552.2
Liabilities assumed:
Accounts payable, trade and other			$	221.9
Accrued and other current liabilities			35.1
Income taxes			78.8
Long-term debt including current portion			301.7
Operating lease liabilities - long-term			53.4
Environmental liabilities			18.9
Deferred income tax liabilities			1,316.7
Other long-term liabilities			49.5
Total liabilities assumed			$	2,076.0
Fair value of net assets acquired			$	3,476.2
Add: Fair value of noncontrolling interests acquired			275.0
Fair value of net assets acquired less noncontrolling interests acquired			$	3,201.2
Goodwill			$	1,189.2

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1.Includes long-term semi-finished goods inventory.

Trade receivables

The $64.2 million of acquired trade receivables represents the fair value of the gross amount due under the contracts.

Property, Plant and Equipment

Property, plant and equipment is inclusive of the fair value of mineral rights totaling $2,745 million and non-mineral rights property, plant and equipment totaling $1,580.5 million. The fair value of the mineral rights was estimated using the multi-period excess earnings method. The excess earnings methodology is an income approach methodology that estimates the projected cash flows of the business attributable to the asset, net of charges for the use of other identifiable assets of the business including working capital, fixed assets, and other intangible assets. Mineral rights are depreciated using a units-of-production method while all other property, plant and equipment is depreciated using the straight-line method.

Goodwill

Goodwill from acquisitions represents the excess of the purchase price over the fair value of net assets acquired. The amount disclosed within the table, subject to change for up to on year subsequent to the Acquisition Date, is attributable to the value of growth opportunities and expected synergies created by incorporating Allkem's business and operations into the Company's operations and the value of the assembled workforce. The goodwill has no amortizable basis for income tax purposes.

Allkem revenues and earnings

The following table represents Allkem's revenues and net earnings included in Arcadium's condensed consolidated statements of operations from the Acquisition Date through March 31, 2024.

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(in Millions)									Three Months Ended March 31,
															2024
Revenue															$	102.5
Income from operations before income taxes															$	78.2

Pro Forma Financial Information

Due to the Allkem Livent Merger closing on January 4, 2024, all activity in the first quarter of 2024 except for the first three days of January, which management deemed not material, is included in Arcadium’s condensed consolidated statements of operations. The following unaudited pro forma financial information for the three months ended March 31, 2023 is based on our historical consolidated financial statements adjusted to reflect the Allkem Livent Merger as if it occurred on January 1, 2023, the first day of the most recently completed fiscal year. The unaudited pro forma financial information is not necessarily indicative of what would have occurred if the Allkem Livent Merger had been completed as of the beginning of the periods presented, nor is it indicative of future results. The unaudited pro forma information is not necessarily indicative of operating results that would have been achieved had the acquisition been completed as of January 1, 2023 and does not intend to project the future financial results of the Company after the acquisition. The unaudited pro forma information is based on certain assumptions, which management believes are reasonable, and does not reflect the cost of any integration activities or synergies that may be derived from any integration activities. The unaudited pro forma financial results are as follows:

(in Millions)									Three Months Ended March 31,
															2023
															(Unaudited)
Revenue															$	569.4
Net income															$	234.1

The following table summarizes the changes in goodwill for the three months ended March 31, 2024.

(in Millions)			Allkem						Nemaska Lithium						Total
Balance as of December 31, 2023			$	—					$	120.7					$	120.7
Acquisitions - Allkem Livent Merger			1,189.2						—						1,189.2
Balance as of March 31, 2024			$	1,189.2					$	120.7					$	1,309.9

See Note 4 for further details.

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Disaggregation of revenue

We disaggregate revenue from contracts with customers by geographical areas (based on product destination) and by product categories. The following table provides information about disaggregated revenue by major geographical region:

(in Millions)									Three Months Ended March 31,
															2024						2023
Asia Pacific (1)															$	220.1					$	167.0
North America (1)															20.7						51.9
Europe, Middle East & Africa															19.6						32.8
Latin America															0.8						1.8
Consolidated Revenue															$	261.2					$	253.5

1.During the three months ended March 31, 2024, countries with sales in excess of 10% of consolidated revenue consisted of China, Japan, and South Korea. Sales for the three months ended March 31, 2024 for China, Japan, and South Korea totaled $125.9 million, $46.0 million, and $45.5 million, respectively. During the three months ended March 31, 2023, countries with sales in excess of 10% of consolidated revenue consisted of China, the U.S., South Korea, and Japan. Sales for the three months ended March 31, 2023 for China, the U.S., South Korea, and Japan totaled $88.4 million, $50.2 million, and $35.1 million, and $33.4 million, respectively.

For the three months ended March 31, 2024, three customers accounted for approximately 22%, 16%, and 14%, respectively, of consolidated revenue and our 10 largest customers accounted in aggregate for approximately 79% of consolidated revenue. For the three months ended March 31, 2023, two customers accounted for approximately 25% and 19% of consolidated revenue and our 10 largest customers accounted in aggregate for approximately 68% of consolidated revenue. A loss of any material customer could have a material adverse effect on our business, financial condition and results of operations.

The following table provides information about disaggregated revenue by major product category:

(in Millions)									Three Months Ended March 31,
															2024						2023
Lithium Hydroxide															$	110.6					$	152.7
Lithium Carbonate (1)															79.8						9.5
Butyllithium and Other Lithium Specialties															46.0						91.3
Spodumene Concentrate (2)															24.8						—
Consolidated Revenue															$	261.2					$	253.5

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1.Includes lithium carbonate by-product revenue.

2.Includes low-grade spodumene sales and minimal other products.

Contract asset and contract liability balances

We satisfy our obligations by transferring goods and services in exchange for consideration from customers. The timing of performance sometimes differs from the timing the associated consideration is received from the customer, thus resulting in the recognition of a contract asset or liability. Provisional pricing within certain of our customer contracts may result in recognition

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of a contract asset or liability. We recognize a contract liability if the customer’s payment of consideration is received prior to completion of our related performance obligation.

The following table presents the opening and closing balances of our contract liabilities and current trade receivables, net of allowances from contracts with customers.

(in Millions)			Balance as of March 31, 2024						Balance as of December 31, 2023						(Decrease)/increase
Receivables from contracts with customers, net of allowances			$	93.5					$	106.7					$	(13.2)
Contract liability - short-term			30.6						4.4						26.2
Contract liability - long-term			218.3						217.8						0.5

Performance obligations

Inventories consisted of the following:

(in Millions)			March 31, 2024						December 31, 2023
Finished goods			$	114.1					$	59.1
Semi-finished goods			122.2						108.8
Raw materials, supplies, and other			92.5						49.6
Inventory, net			$	328.8					$	217.5

Investments consisted of the following:

(in Millions)			March 31, 2024						December 31, 2023
ESM ILiAD, LLC			$	30.1					$	30.1
Arcadium NQSP			6.0						4.7
Other			2.5						—
Investments			$	38.6					$	34.8

ESM ILiAD, LLC ("ESM")

In the fourth quarter of 2023, the Company entered into an agreement with EnergySource Minerals, LLC ("EnergySource"), a developer of lithium projects in the Salton Sea Known Geothermal Resource Area in California, for a minority equity interest in ESM, a subsidiary of EnergySource and the parent company of ILiAD Technologies, LLC ("ILiAD Technologies"). In connection with its investment in ESM, Arcadium Lithium will have the right to license ILiAD Technologies' Integrated Lithium Adsorption Desorption ("ILiAD") technology for potential deployment at its lithium brine resources in Argentina.

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Arcadium Lithium accounts for its interest in ESM under ASC Topic 321, Investments – Equity Securities ("ASC 321"). Since our investment in ESM does not have a readily determinable fair value, we use the measurement alternative under ASC 321. Our investment is measured at cost less impairments, adjusted for observable price changes in orderly transactions for the identical or similar investment of the same issuer. If the Company determines that an indicator of impairment or upward adjustment is present, an adjustment is recorded, which is measured as the difference between carrying value and estimated fair value. Estimated fair value is generally determined using an income approach on discounted cash flows or negotiated transaction values. As of March 31, 2024 and December 31, 2023, the carrying amount of our investment in ESM was $30.1 million.

Toyotsu Lithium Corporation ("TLC")

The Company owns 49% of the Class A voting shares and 100% of the Class B non-voting shares in TLC. Toyota Tsusho Corporation ("TTC") owns 51% of the Class A voting shares. As a result, the Company has a 75% economic interest and a 49% ownership interest in TLC and TTC has the remaining 25% economic interest and 51% ownership interest in TLC. TLC constructed and now operates the Naraha Lithium Hydroxide Plant (the "Naraha Plant"), located in Japan. The technical grade lithium carbonate feedstock for the plant is sourced from the Company’s Olaroz Plant.

The Company accounts for its interest in TLC as an equity method investment because it does not have control but has significant influence. This is evidenced by the Company having 2 of the 5 board members while decisions are made by a majority. In addition to capital contributions made through its investment in TLC, Allkem has also provided past funding through loans. At the Acquisition Date, the carrying values of the investment in TLC and a fully reserved loan receivable were zero and fair value was deemed to be equal to carrying value.

For the three months ended March 31, 2024, we did not record any gains or losses related to our interest in TLC to Equity in net loss of unconsolidated affiliates in our condensed consolidated statements of operations. At March 31, 2024, the carrying values of our interest in TLC and the loan receivable were zero.

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Nemaska Lithium Inc. ("Nemaska Lithium", or "NLI")

Nemaska Lithium, domiciled in Canada and headquartered in Montreal, Québec, is a non-public lithium company not yet in the production stage. It is a development company aiming to vertically integrate, from extracting, processing and concentrating spodumene to conversion of spodumene into battery-grade lithium hydroxide, primarily intended for EV and other energy storage applications. Its primary assets are construction in progress and intangibles principally related to intellectual property. Nemaska Lithium intends to develop the Whabouchi spodumene mine and concentrator in the James Bay region of Québec and a lithium hydroxide conversion plant in Bécancour, Québec (collectively, the "Nemaska Lithium Project"). As a developing company and to fund the Nemaska Lithium Project, Nemaska Lithium is reliant on securing financing from its shareholders through share subscriptions.

On October 18, 2023, we entered into an amendment to our shareholders agreement with Nemaska Lithium, and also amendments to certain related service agreements. The amendments to these agreements provide QLP with control of certain substantive participating rights, and as such, the Company began to consolidate Nemaska Lithium as of October 18, 2023. Nemaska Lithium is a development company which, as of the October 18, 2023 consolidation date, met the U.S. GAAP definition of a business and, as such, the Company remeasured its equity interest in Nemaska, including the noncontrolling interest of Investissement Québec ("IQ"), at fair value as of the consolidation date. We estimated the fair value of IQ's noncontrolling interest by multiplying the total fair value of Nemaska Lithium equity by IQ's equity ownership interest and also considered any discounts for lack of control and marketability.

The fair value of the assets and liabilities of Nemaska Lithium assumed under business combination accounting guidance for the Nemaska Lithium consolidation, including the impact of income taxes, is preliminary. The preliminary fair value allocation is subject to change for up to one year subsequent to the October 18, 2023 consolidation date of Nemaska Lithium. Determining the fair value of the assets and liabilities of Nemaska Lithium requires judgment and certain assumptions to be made, the most significant of these being related to the valuation of Nemaska Lithium's mining properties and rights. Nemaska Lithium is consolidated on a one-quarter lag basis.

Before October 18, 2023, the Company accounted for its 50% interest in Nemaska Lithium as an equity method investment on a one-quarter lag basis and it was included in Investments in our consolidated balance sheets. The carrying amount of our interest in Nemaska Lithium was $437.1 million as of December 31, 2022 under equity method investment accounting. For the three months ended March 31, 2023 we recorded a $8.1 million loss related to our interest in Nemaska Lithium to Equity in net loss of unconsolidated affiliate in our condensed consolidated statements of operations.

Arcadium's cash and cash equivalents balance in its condensed consolidated balance sheet as of March 31, 2024 includes Nemaska Lithium's cash of $43 million at December 31, 2023 as Nemaska Lithium is consolidated on a one-quarter lag. All cash at Nemaska Lithium will be used for capital expenditures and operating expenses of the Nemaska Lithium Project.

On March 28, 2024, Nemaska Lithium received cash of $150 million related to a second advance payment in connection with a customer supply agreement repayable in equal quarterly installments beginning in January 2027 and ending in October 2031. The related liability will be $97.8 million debt and $52.2 million contract liability. A total of $350 million in prepayments are expected from the customer and as of March 31, 2024, $225 million has been received.

Sales de Jujuy Pte Ltd and Sales de Jujuy S.A.

The Company has an interest of 72.68% in Sales de Jujuy Pte Ltd ("SDJ Pte"), 66.5% in Sales de Jujuy S.A. ("SDJ SA"), the legal entities which operate the Olaroz Lithium Facility (the "Olaroz Plant").

Located in the Jujuy Province of northern Argentina, the Olaroz Plant produces lithium carbonate chemicals for the battery, technical and chemical markets. The Olaroz Plant is operated through SDJ SA, which is a 91.5% owned subsidiary of SDJ Pte, a Singaporean company owned by Arcadium (72.68%) and Toyotsu Lithium Pte Ltd. (27.32%), an affiliated company of TTC. Jujuy Energia y Minera Sociedad del Estado ("JEMSE") owns the remaining 8.5% of SDJ SA. Consequently, the effective equity ownership of the Olaroz Plant is 66.5% by Arcadium, 25% by TTC, and 8.5% by JEMSE.

As of March 31, 2024, Arcadium had cash set aside of $24.6 million in other noncurrent assets in its condensed consolidated balance sheets for the guarantee of SDJ SA's Olaroz Project Loan Facility for Stage 1 and Stage 2. See Note 14 for details.

Arcadium's cash and cash equivalents balance in its condensed consolidated balance sheet as of March 31, 2024 includes $89.5 million held by the entities discussed above.

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Arcadium funded JEMSE’s equity contributions in SDJ SA with an interest-free loan (the "JEMSE Receivable") to be repaid by JEMSE out of 33% of the dividends it receives from SDJ SA. The fair value of the non-current receivable is $5.5 million as of March 31, 2024.

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Property, plant and equipment consisted of the following:

(in Millions)			March 31, 2024						December 31, 2023
Land and land improvements			$	325.2					$	106.2
Buildings			724.5						134.9
Machinery and equipment			791.6						420.7
Mineral rights			3,278.0						560.0
Construction in progress			1,953.5						1,284.4
Total cost			$	7,072.8					$	2,506.2
Accumulated depreciation			(279.1)						(269.1)
Property, plant and equipment, net			$	6,793.7					$	2,237.1

Depreciation is calculated principally on a straight-line basis over the estimated useful lives of the assets or a units-of-production basis based on the rate of depletion of reserves. Land is not depreciated. The major classifications of property, equipment and software, including their respective principal depreciation and amortization method and expected useful lives, consisted of the following:

Asset type			Depreciation and amortization method			Useful Life
Land			N/A			—
Land improvements			Straight-line			20 years
Buildings			Straight-line			20-40 years
Mineral rights			Units-of-production			Based on rate of depletion of reserves
Mining extraction equipment			Units-of-production			Based on rate of depletion of reserves
Leased plant and equipment			Straight-line			Lease period (1-10.5 years)
Other machinery and equipment			Straight-line			3-18 years
Software			Straight-line			3-10 years

Depreciation expense was $15.4 and $6.1 million for the three months ended March 31, 2024 and 2023, respectively.

The following table shows other charges included in "Restructuring and other charges" in the condensed consolidated statements of operations:

									Three Months Ended March 31,
(in Millions)															2024						2023
Restructuring charges:
Severance-related and exit costs															$	10.9					$	1.7
Other charges:
Costs related to the Allkem Livent Merger															67.0						—
Other															5.7						0.2
Total Restructuring and other charges															$	83.6					$	1.9

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We determine our interim tax provision using an estimated annual effective tax rate methodology ("EAETR") in accordance with U.S. GAAP. The EAETR is applied to the year-to-date ordinary income, exclusive of discrete items. The tax effects of discrete items are then included to arrive at the total reported interim tax provision.

The determination of the EAETR is based upon a number of estimates, including the estimated annual pretax ordinary income in each tax jurisdiction in which we operate. As our projections of ordinary income change throughout the year, the EAETR will change period-to-period. The tax effects of discrete items are recognized in the tax provision in the period they occur in accordance with U.S. GAAP. Depending on various factors, such as the item’s significance in relation to total income and the rate of tax applicable in the jurisdiction to which it relates, discrete items in any quarter can materially impact the reported effective tax rate. As a global enterprise, our tax expense can be impacted by changes in tax rates or laws, the finalization of tax audits and reviews, as well as other factors. As a result, there can be significant volatility in interim tax provisions.

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Long-term debt

Long-term debt consists of the following:

			Interest Rate Percentage																		Maturity Date						March 31, 2024						December 31, 2023
(in Millions)			SOFR borrowings						Base rate borrowings
Revolving Credit Facility (1)			7.18%						9.25%												2027						$	—					$	—
4.125% Convertible Senior Notes due 2025															4.125%						2025						245.8						245.8
Transaction costs - 2025 Notes																											(2.0)						(2.4)
Nemaska - Prepayment agreement (2)															8.9%												75.0						75.0
Discount - Prepayment agreement																											(20.2)						(19.8)
Nemaska - Other																											0.4						3.4
Debt assumed in Allkem Livent Merger
Project Loan Facility - Stage 1 of Olaroz Plant															4.896%						2024						9.2						—
Project Loan Facility - Stage 2 of Olaroz Plant															2.612%						2029						144.0						—
Project Financing Facility - Sal de Vida															10.051%						2030						47.0						—
Affiliate Loans with TTC															11.331%						2030						81.6						—
Affiliate Loan with TLP															10.34%						2026						2.5						—
Total debt assumed in Allkem Livent Merger																											284.3						—
Subtotal long-term debt (including current maturities)																											583.3						302.0
Less current maturities																											$	(80.6)					$	(2.4)
Total long-term debt																											$	502.7					$	299.6

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1.As of March 31, 2024 and December 31, 2023, there were $15.5 million in letters of credit outstanding under our Revolving Credit Facility and $484.5 million available funds. Fund availability is subject to the Company meeting its debt covenants.

2.Represents first advance payment in connection with customer supply agreement repayable in equal quarterly installments beginning in January 2027 and ending in October 2031. Represents U.S. GAAP imputed interest rate. On March 28, 2024, Nemaska Lithium received a second advance payment of $150 million in connection with the customer supply agreement, with a discount of $52.2 million.

4.125% Convertible Senior Notes due 2025

In 2020, the Company issued $245.8 million in aggregate principal amount of 4.125% Convertible Senior Notes due in July 2025 (the "2025 Notes"). The 2025 Notes are our general unsecured senior obligations. Total net cash proceeds received were $238.2 million net of $7.6 million of third-party transaction costs, including initial purchasers' discounts and commissions. The Company used or will use the net proceeds received to finance or refinance eligible green projects designed to align with the provisions of the International Capital Market Association Green Bond Principles 2018.

Each $1,000 of principal of the 2025 Notes was initially convertible into 114.4885 shares of common stock of Livent Corporation, which was equivalent to an initial conversion price of $8.73 per share, subject to adjustment upon the occurrence of specified events. Following the effectiveness of that certain First Supplemental Indenture, dated as of January 4, 2024, by and among the Company, Livent Corporation and U.S. Bank Trust Company, National Association, each $1,000 of principal of the 2025 Notes is convertible into 275.459331 shares of our ordinary shares, which is equivalent to a conversion price of $3.63 per share, subject to adjustment upon the occurrence of specified events. We may redeem for cash all or any portion of the 2025 Notes, at our option, if the last reported sale price of our ordinary shares has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the 2025 Notes to be redeemed, plus accrued and unpaid interest. Holders of the 2025 Notes may convert their notes at any time, at their option, on or after January 15, 2025. Further, holders of the 2025 Notes may convert their notes at any time, at their option, prior to January 15, 2025 only

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under the following circumstances: (1) during any calendar quarter commencing after September 30, 2020 (and only during such calendar quarter), if the last reported sale price of our ordinary shares for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each trading day; (2) during the five-business day period after any five-consecutive trading day period in which the trading price per $1,000 principal amount of the 2025 Notes for each trading day of such period is less than 98% of the product of the last reported sale price of our ordinary shares and the conversion rate on each such trading day, (3) if we call any or all of the 2020 Notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date or (4) if specified corporate events occur. Upon conversion, the 2025 Notes will be settled in cash, shares of our ordinary shares or a combination thereof, at our election. If a fundamental change occurs prior to the maturity date, holders of the 2025 Notes may require us to repurchase all or a portion of their 2025 Notes for cash at a repurchase price equal to 100% of the principal amount plus any accrued and unpaid interest. In addition, if specific corporate events occur prior to the maturity date or if we deliver a notice of redemption, we will increase the conversion rate for a holder who elects to convert its 2025 Notes in connection with such an event or notice of redemption in certain circumstances.

The last reported sale price of our ordinary shares for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on, and including, March 31, 2024 was not greater than or equal to 130% of the conversion price as adjusted for the Allkem Livent Merger, which is $4.72, on each trading day, and as a result, the holders do not have the option to convert all or any portion of their 2025 Notes through June 30, 2024.

The conversion rate for the 2025 Notes is 275.4593 ordinary shares of Arcadium Lithium per $1,000 principal amount of 2025 Notes. The 2025 Notes mature in July 2025 and are classified as long-term debt.

The Company recognized non-cash interest related to the amortization of transaction costs for the 2025 Notes of $0.4 million for the three months ended March 31, 2024, all of which was capitalized. The Company recorded $2.5 million of accrued interest expense related to the principal amount for the three months ended March 31, 2024, all of which was capitalized.

Amended and Restated Credit Agreement, (the "Revolving Credit Facility")

On January 4, 2024, Livent Corporation, Livent USA Corp., the Company, Arcadium Lithium Financing IRL Limited ("FinCo") and Irish IntermediateCo (collectively, the "Borrowers" and, each, a "Borrower"), the guarantors party thereto from time to time (the "Guarantors"), the lenders party thereto (the "Lenders") and issuing banks party thereto and Citibank, N.A., as administrative agent (the "Administrative Agent") for the Lenders, entered into a Joinder and First Amendment (the "Credit Agreement Amendment") to that certain Amended and Restated Credit Agreement, dated as of September 1, 2022, among Livent, Livent USA Corp., the guarantors party thereto from time to time, the lenders party thereto from time to time and the Administrative Agent (the "Credit Agreement" and as amended by the Credit Agreement Amendment, the Amended Credit Agreement").

The Credit Agreement Amendment provided for, among other things, (i) the addition of Arcadium, Irish IntermediateCo and FinCo as borrowers and obligors under the Amended Credit Agreement and (ii) the assignment of certain of Livent Corporation's rights and obligations (including information reporting obligations) under the Amended Credit Agreement to Arcadium.

The Revolving Credit Facility provides for a $500 million senior secured revolving credit facility, $50 million of which is available for the issuance of letters of credit for the account of the Borrowers, with an option to request, and subject to each Lender’s sole discretion, that the aggregate revolving credit commitments be increased to up to $700 million. The issuance of letters of credit and the proceeds of revolving credit loans made pursuant to the Revolving Credit Facility may be used for general corporate purposes, including capital expenditures and permitted acquisitions.

Revolving loans under the Revolving Credit Facility will bear interest at a floating rate, which will be (i) a base rate, (ii) Adjusted Term Secured Overnight Financing Rate ("SOFR") (defined as the forward-looking SOFR term rate published by CME Group Benchmark Administration Limited plus 0.10% per annum subject to a floor of zero) or (iii) Euro Interbank Offered Rate ("EURIBOR"), plus, in each case, an applicable margin, as determined in accordance with the provisions of the Revolving Credit Facility. The Revolving Credit Facility includes a quarterly commitment fee on the average daily unused amount of each Lender’s revolving credit commitment at a rate equal to an applicable percentage based on the Company’s first lien leverage ratio. The initial commitment fee is 0.25% per annum. Amounts under the Revolving Credit Facility may be borrowed, repaid and re-borrowed from time to time until the final maturity date on September 1, 2027. Voluntary prepayments and commitment reductions are permitted at any time without payment of any prepayment fee upon proper notice and subject to minimum dollar amounts. Certain of the Borrowers’ domestic subsidiaries (the "Guarantors") guarantee the obligations of the Borrowers under the Revolving Credit Facility. The obligations of the Borrower and the Guarantors are secured by all of the

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assets of the Borrowers and the Guarantors, including the Borrowers’ facility and real estate in Bessemer City, North Carolina, subject to certain exceptions and exclusions.

We recorded $0.8 million of incremental deferred financing costs in the condensed consolidated balance sheets for the Revolving Credit Facility commitment and legal fees and a $0.2 million loss on debt extinguishment in the condensed consolidated statements of operations for the three months ended March 31, 2024 for the write off of existing deferred financing costs to recognize a partial change in syndication related to the Revolving Credit Facility. The carrying value of our deferred financing costs was $2.7 million as of March 31, 2024 and is recorded to Other assets in our condensed consolidated balance sheet.

Covenants

The Credit Agreement contains certain affirmative and negative covenants that are binding on us and our subsidiary, Livent USA Corp., as borrowers (the "Borrowers") and their subsidiaries, including, among others, restrictions (subject to exceptions and qualifications) on the ability of the Borrowers and their subsidiaries to create liens, to undertake fundamental changes, to incur debt, to sell or dispose of assets, to make investments, to make restricted payments such as dividends, distributions or equity repurchases, to change the nature of their businesses, to enter into transactions with affiliates and to enter into certain restrictive agreements. Furthermore, the Borrowers are subject to financial covenants regarding leverage (measured as the ratio of debt to adjusted earnings) and interest coverage (measured as the ratio of adjusted earnings to interest expense). Our maximum allowable first lien leverage ratio is 3.5 as of March 31, 2024. Our minimum allowable interest coverage ratio is 3.5. We were in compliance with all requirements of the covenants as of March 31, 2024.

Debt assumed as a result of Allkem Livent Merger

The following is a summary of Allkem's indebtedness that Arcadium Lithium assumed as a result of the Allkem Livent Merger.

Project Loan Facility

SDJ SA has a project loan facility with Mizuho Bank related to the Olaroz Plant (the "Project Loan Facility"):

•The Project Loan Facility for Stage 1 of the Olaroz Plant had an outstanding principal balance of $9.2 million as of March 31, 2024. The interest rate for the Stage 1 loan is the SOFR plus a margin of 0.80%. The interest rate related to 88.6% of the loan was hedged in 2015 with such rate currently at 4.896% until the last repayment in September 2024. Sales de Jujuy Pte Ltd has provided security in favor of Mizuho Bank over the shares it owns in SDJ SA and the Japan Organization for Metals and Energy Security, which covers 82.35% of the outstanding principal amount; and

•The Project Loan Facility for Stage 2 of the Olaroz project had an outstanding balance of $144.0 million as of March 31, 2024. The interest rate for the Stage 2 loan is a fixed rate of 2.6119% per annum until expiry in March 2029.

As of March 31, 2024, Arcadium had cash set aside of $24.6 million in other noncurrent assets in its condensed consolidated balance sheets for the guarantee of the Project Loan Facility.

Under an arrangement with TTC, Arcadium has reserved $77.8 million as a cash guarantee for the Olaroz Plant Project Loan Facility.

Project Financing Facility

Galaxy Lithium (SAL DE VIDA) S.A. ("SDV SA"), which is owned 100% by Arcadium, entered into a project financing facility with the International Finance Corporation related to the Sal de Vida development project ("Sal de Vida") in Argentina (the "Project Financing Facility"). The Project Financing Facility originally provided for a total of $180.0 million in limited recourse, sustainability-linked green project financing maturing in March 2033, with repayment commencing in March 2026. The Project Financing Facility had an outstanding principal balance of $47.0 million as of March 31, 2024. Arcadium Lithium expects to pay off the balance of the Project Financing Facility in the second quarter of 2024. The interest rate for the Project Financing Facility is term SOFR plus a margin of 4.8% with adjustments of up to +/- 0.25% based on the performance against agreed sustainability targets, as measured at June 2026, 2028 and 2030. The Project Financing Facility is supported by an Arcadium Lithium parent guarantee until completion of construction and subject to affirmative and negative covenants. As of March 31, 2024, Arcadium had cash set aside of $32.5 million in other noncurrent assets in its condensed consolidated balance sheets for the guarantee of the Project Financing Facility.

Affiliate Loans With TTC

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Arcadium Lithium plc Omnibus Incentive Plan (the "Arcadium Plan")

As of March 31, 2024, there were 64,548,000 Arcadium ordinary shares authorized for issuance under the Arcadium Plan. The Arcadium Plan provides for the grant of a variety of cash and equity awards to officers, directors, employees and consultants, including share options, restricted shares, restricted share units (including performance units), share appreciation rights, and management incentive awards. The Compensation Committee of the Arcadium Board of Directors (the "Arcadium Committee") has the authority to amend the Arcadium Plan at any time, approve financial targets, award grants, establish performance objectives and conditions and the times and conditions for payment of awards.

Share options granted under the Arcadium Plan may be incentive or non-qualified share options. The exercise price for share options may not be less than the fair market value of the share at the date of grant. Awards granted under the Arcadium Plan vest or become exercisable or payable at the time designated by the Arcadium Committee. The options granted in 2024 will vest on the first, second and third anniversaries of the date of grant, subject generally to continued employment, and cost is recognized over the vesting period. Incentive and non-qualified options granted under the Arcadium Plan expire not later than 10 years from the grant date.

Under the Arcadium Plan, awards of restricted share units ("RSUs") vest over periods designated by the Arcadium Committee. The RSUs granted in 2024 to employees will vest equally on the first, second and third anniversaries of the grant date, subject generally to continued employment, and cost is recognized over the vesting period. The RSUs granted to non-employee directors in 2024 vest at the Company's next annual meeting of shareholders following the grant date. Compensation cost is recognized over the vesting periods based on the market value of Arcadium ordinary shares on the grant date of the award.

Allkem Replacement Awards

Pursuant to the Transaction Agreement, the equity awards of Allkem (including performance rights) outstanding as of immediately prior to the closing of the Allkem Livent Merger were converted into equity awards denominated in shares of Arcadium ordinary shares. The Company issued time-based vesting restricted shares in connection with the conversion of such awards. The estimated fair value of the portion of the Allkem equity awards for which the required service period had been completed at the time of the closing of the Allkem Livent Merger was treated as purchase consideration. The remaining estimated fair value is recorded as compensation expense over the remainder of the service period associated with the awards. The Allkem Replacement Awards are authorized for issuance under the Arcadium Plan.

Legacy Livent Awards

As of March 31, 2024, there were 6,579,305 Arcadium ordinary shares authorized for issuance upon the exercise or settlement of the Legacy Livent Awards.

Share Compensation

We recognized the following share compensation expense for Legacy Livent Awards and awards under the Arcadium Plan:

			Three Months Ended March 31,
(in Millions)			2024
Share Option Expense, net of taxes of $0.1			$	0.4
Restricted Share Expense, net of taxes of $0.7			12.4
Performance-Based Restricted Share Expense, net of taxes of less than $0.1			0.4
Total Share Compensation Expense, net of taxes of $0.8 (1)			$	13.2

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(1)    Gross share compensation charges of $2.3 million and $13.5 million were recorded to "Selling, general and administrative expenses" and "Restructuring and other charges", respectively, in our condensed consolidated statements of operations for the three months ended March 31, 2024.

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Share Options

The grant date fair values of the share options granted in the three months ended March 31, 2024, were estimated using the Black-Scholes option valuation model, the key assumptions for which are listed in the table below. The expected volatility assumption is based on the historical volatility of a group of ten of our publicly traded peers that operate in the specialty chemical sector. The expected life represents the period of time that options granted are expected to be outstanding. The risk-free interest rate is based on U.S. Treasury securities with terms equal to the expected timing of share option exercises as of the grant date. The dividend yield assumption reflects anticipated dividends on Arcadium's ordinary shares. Arcadium share options granted in the three months ended March 31, 2024 will vest equally on the first, second and third anniversaries of the grant date and expire ten years from the date of grant.

Black Scholes valuation assumptions for Arcadium Plan share option grants: 

			Three Months Ended March 31, 2024
Expected dividend yield			—%
Expected volatility			31.18%
Expected life (in years)			6.0
Risk-free interest rate			4.08%

The weighted-average grant date fair value of share options granted during the three months ended March 31, 2024 was $1.91 per share.

The following summary shows share option activity for the Allkem Livent Merger and the Arcadium Plan for the three months ended March 31, 2024:

			Number of Options Granted But Not Exercised						Weighted-Average Remaining Contractual Life (in Years)						Weighted-Average Exercise Price Per Share						Aggregate Intrinsic Value (in Millions)
Outstanding December 31, 2023			5,060,687						5.6 years						$	6.73					$	6.5
Granted			2,517,175												$	4.95
Exercised			(53,056)												$	4.05					$	—
Outstanding March 31, 2024			7,524,806						6.6						$	6.28					$	0.8
Exercisable at March 31, 2024			4,142,996						4.9						$	6.25					$	0.8

As of March 31, 2024, we had total remaining unrecognized compensation cost related to unvested share options of $5.5 million which will be amortized over the weighted-average remaining requisite service period of approximately 1.6 years.

Restricted Share Unit Awards

The grant date fair value of RSUs under the Arcadium Plan is based on the market price per share of Arcadium's ordinary shares on the date of grant, and the related compensation cost is amortized to expense on a straight-line basis over the vesting period during which the employees perform related services, which for the RSUs granted during the three months ended March 31, 2024, will vest equally on the first, second and third anniversaries of the grant date.

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Pursuant to the Transaction Agreement, on the Acquisition Date, 927,510 employee RSUs vested on an accelerated pro rata basis. The following table shows RSU activity for the Allkem Livent Merger and the Arcadium Plan for the three months ended March 31, 2024:

			Restricted Share Units
			Number of awards						Weighted-Average Grant Date Fair Value						Aggregate Intrinsic Value (in Millions)
Nonvested December 31, 2023			2,287,088						$	7.83					$	17.1
Granted (1)			2,238,079						$	5.99
Vested (2)			(1,816,439)						$	7.11
Nonvested March 31, 2024			2,708,728						$	6.83					$	10.5

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1.The Company granted 1,080,825 Allkem Replacement Awards on January 12, 2024 pursuant to the Transaction Agreement.

2.Immediately prior to the Acquisition Date, 768,440 non-employee Director RSUs vested and were paid out in cash of $5.3 million pursuant to the Transaction Agreement.

As of March 31, 2024, the Arcadium Plan had total remaining unrecognized compensation cost related to unvested RSUs of $13.3 million which will be amortized over the weighted-average remaining requisite service period of approximately 1.7 years.

Performance-Based Restricted Share Unit ("PRSU") Awards

Pursuant to the Transaction Agreement, on the Acquisition Date, 96,885 employee PRSUs vested on an accelerated basis at the higher of the PRSU payout on the accelerated vest date, which was —%, or 100%. The following table shows PRSU activity for the three months ended March 31, 2024.

			Performance-Based Restricted Share Units
			Number of awards						Weighted-Average Grant Date Fair Value						Aggregate Intrinsic Value (in Millions)
Nonvested as of December 31, 2023			96,885						$	9.43					$	0.7
Vested			(96,885)						$	9.43
Nonvested as of March 31, 2024			—						$	—					$	—

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After the closing of the Allkem Livent Merger on January 4, 2024 and as of March 31, 2024, we had 5 billion ordinary shares of $1.00 par value each and 125 million preferred shares of $1.00 par value each authorized. The following is a summary of Arcadium's ordinary shares issued and outstanding:

			Issued						Treasury						Outstanding
Balance as of December 31, 2023 (1)			433,059,946						(263,669)						432,796,277
Issued to Allkem shareholders - Allkem Livent Merger			641,337,840						—						641,337,840
PRSU and RSU awards accelerated - Allkem Livent Merger			648,969						—						648,969
Arcadium RSU awards			15,248						—						15,248
Arcadium share option awards			8,497						—						8,497
Net sales of treasury shares - Arcadium NQSP			—						461						461
Balance as of March 31, 2024			1,075,070,500						(263,208)						1,074,807,292

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1.Balances outstanding as of December 31, 2023, representing predecessor Livent, have been adjusted to reflect the 2.406 Exchange Ratio.

Accumulated other comprehensive loss

Summarized below is the roll forward of accumulated other comprehensive loss, net of tax.

(in Millions)			Foreign currency adjustments						Derivative Instruments						Total
Accumulated other comprehensive loss, net of tax as of December 31, 2023			$	(49.8)					$	—					$	(49.8)
Other comprehensive (losses)/income before reclassifications			(20.2)						0.2						(20.0)
Accumulated other comprehensive loss, net of tax as of March 31, 2024			$	(70.0)					$	0.2					$	(69.8)

(in Millions)			Foreign currency adjustments						Derivative Instruments						Total
Accumulated other comprehensive loss, net of tax as of December 31, 2022			$	(51.0)					$	—					$	(51.0)
Other comprehensive income before reclassifications			1.5						0.2						1.7
Accumulated other comprehensive loss, net of tax as of March 31, 2023			$	(49.5)					$	0.2					$	(49.3)

Dividends

Earnings per ordinary share ("EPS") is computed by dividing net income by the weighted average number of common shares outstanding during the period on a basic and diluted basis.

Our potentially dilutive securities include potential ordinary shares related to our share options, restricted share units and 2025 Notes. See Note 12 to our consolidated financial statements in Part II, Item 8 of our 2023 Annual Report on Form 10-K for more information. Diluted earnings per share ("Diluted EPS") considers the impact of potentially dilutive securities except in periods in which there is a loss because the inclusion of the potential ordinary shares would have an anti-dilutive effect. Diluted EPS excludes the impact of potential ordinary shares related to our share options in periods in which the option exercise price is greater than the average market price of our ordinary shares for the period. We use the if-converted method when calculating the potential dilutive effect, if any, of our 2025 Notes.

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Earnings applicable to ordinary shares and ordinary shares used in the calculation of basic and diluted earnings per share are as follows:

(in Millions, Except Share and Per Share Data)									Three Months Ended March 31,
															2024						2023 (1)
Numerator:
Net income attributable to Arcadium Lithium plc															$	15.6					$	114.8
Denominator:
Weighted average ordinary shares outstanding - basic															1,053.4						432.0
Dilutive share equivalents from share-based plans															1.0						3.6
Dilutive share equivalents from 2025 Notes															67.7						67.7
Weighted average ordinary shares outstanding - diluted															1,122.1						503.3
Basic earnings per ordinary share															$	0.01					$	0.27
Diluted earnings per ordinary share															$	0.01					$	0.23

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1.For the three months ended March 31, 2023, weighted average ordinary shares outstanding - basic and diluted, dilutive share equivalents and basic and diluted earnings per ordinary share amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio.

Anti-dilutive share options

For the three months ended March 31, 2024, options to purchase 3,683,694 shares of our ordinary shares, respectively, at an average exercise price of $7.87 per share were anti-dilutive and not included in the computation of diluted earnings per share because the exercise price of the options was greater than the average market price of the ordinary shares for the three months ended March 31, 2024. For the three months ended March 31, 2023, options to purchase 438,154 shares of our ordinary shares, respectively, at an average exercise price of $9.70 per share were anti-dilutive and not included in the computation of diluted earnings per share because the exercise price of the options was greater than the average market price of the ordinary shares for the three months ended March 31, 2023.

Our financial instruments include cash and cash equivalents, trade receivables, other current assets, investments held in trust fund, trade payables, derivatives and amounts included in accruals meeting the definition of financial instruments. Investments in the Arcadium NQSP deferred compensation plan trust fund are considered Level 1 investments based on readily available quoted prices in active markets for identical assets. The carrying value of cash and cash equivalents, trade receivables, other current assets, and trade payables approximates their fair value due to their short-term nature and are considered Level 1 investments. Our other financial instruments include the following:

Financial Instrument						Valuation Method
Foreign exchange forward contracts						Estimated amounts that would be received or paid to terminate the contracts at the reporting date based on current market prices for applicable currencies.

The estimated fair value of our foreign exchange forward contracts has been determined using standard pricing models which take into account the present value of expected future cash flows discounted to the balance sheet date. These standard pricing models utilize inputs derived from, or corroborated by, observable market data such as currency and commodity spot and forward rates.

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The inputs used to measure fair value are classified into the following hierarchy:

Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities.

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Level 2 - Unadjusted quoted prices in active markets for similar assets or liabilities, or unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs other than quoted prices that are observable for the asset or liability.

Level 3 - Unobservable inputs for the asset or liability.

The estimated fair value and the carrying amount of debt were $688.9 million and $583.3 million, respectively, as of March 31, 2024. Our 2025 Notes are classified as Level 2 in the fair value hierarchy.

Use of Derivative Financial Instruments to Manage Risk

We mitigate certain financial exposures connected to currency risk through a program of risk management that includes the use of derivative financial instruments. We enter into foreign exchange forward contracts to reduce the effects of fluctuating foreign currency exchange rates.

We formally document all relationships between hedging instruments and hedged items, as well as the risk management objective and strategy for undertaking various hedge transactions. This process includes relating derivatives that are designated as fair value or cash flow hedges to specific assets and liabilities on the balance sheet or to specific firm commitments or forecasted transactions. We also assess both at the inception of the hedge and on an ongoing basis, whether each derivative is highly effective in offsetting changes in fair values or cash flows of the hedged item. If we determine that a derivative is not highly effective as a hedge, or if a derivative ceases to be a highly effective hedge, we discontinue hedge accounting with respect to that derivative prospectively.

Foreign Currency Exchange Risk Management

We conduct business in many foreign countries, exposing earnings, cash flows, and our financial position to foreign currency risks. The majority of these risks arise as a result of foreign currency transactions. The primary currencies for which we have exchange rate exposure are the Euro, the British pound, the Chinese yuan, the Argentine peso, the Australian dollar, the Canadian dollar and the Japanese yen. We currently do not hedge foreign currency risks associated with the Argentine peso due to the limited availability and the high cost of suitable derivative instruments. Our policy is to minimize exposure to adverse changes in currency exchange rates. This is accomplished through a controlled program of risk management that could include the use of foreign currency debt and forward foreign exchange contracts. We also use forward foreign exchange contracts to hedge firm and highly anticipated foreign currency cash flows, with an objective of balancing currency risk to provide adequate protection from significant fluctuations in the currency markets.

Concentration of Credit Risk

Our counterparties to derivative contracts are primarily major financial institutions. We limit the dollar amount of contracts entered into with any one financial institution and monitor counterparties’ credit ratings. We also enter into master netting agreements with each financial institution, where possible, which helps mitigate the credit risk associated with our financial instruments. While we may be exposed to credit losses due to the nonperformance of counterparties, we consider this risk remote.

Accounting for Derivative Instruments and Hedging Activities

Cash Flow Hedges

We recognize all derivatives on the balance sheet at fair value. On the date we enter into the derivative instrument, we generally designate the derivative as a hedge of the variability of cash flows to be received or paid related to a forecasted transaction (cash flow hedge). We record in accumulated other comprehensive loss ("AOCL") changes in the fair value of derivatives that are designated as and meet all the required criteria for, a cash flow hedge. We then reclassify these amounts into earnings as the underlying hedged item affects earnings. In contrast, we immediately record in earnings changes in the fair value of derivatives that are not designated as cash flow hedges. As of March 31, 2024, we had open foreign currency forward contracts in AOCL in a net after-tax gain position of $0.2 million designated as cash flow hedges of underlying forecasted sales and purchases. As of March 31, 2024, we had open forward contracts with various expiration dates to buy, sell or exchange foreign currencies with a U.S. dollar equivalent of approximately $32.3 million.

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A net after-tax gain of $0.2 million, representing open foreign currency exchange contracts, will be realized in earnings during the year ending December 31, 2024 if spot rates in the future are consistent with market rates as of March 31, 2024. The actual effect on earnings will be dependent on the actual spot rates when the forecasted transactions occur. We recognize derivative gains and losses in the “Cost of sales” line in the condensed consolidated statements of operations.

Derivatives Not Designated As Cash Flow Hedging Instruments

We hold certain forward contracts that have not been designated as cash flow hedging instruments for accounting purposes. Contracts used to hedge the exposure to foreign currency fluctuations associated with certain monetary assets and liabilities are not designated as cash flow hedging instruments and changes in the fair value of these items are recorded in earnings.

We had open forward contracts not designated as cash flow hedging instruments for accounting purposes with various expiration dates to buy, sell or exchange foreign currencies with a U.S. dollar equivalent of approximately $87.1 million as of March 31, 2024.

Fair Value of Derivative Instruments

The following table provides the gross fair value and net balance sheet presentation of our derivative instruments. The Company had no open derivative cash flow hedge contracts as of December 31, 2023.

			March 31, 2024
			Gross Amount of Derivatives
(in Millions)			Designated as Cash Flow Hedges
Derivative assets
Foreign exchange contracts			$	0.2
Total derivative assets (1)			0.2
Net derivative assets			$	0.2

__________________

1.Net balance is included in “Prepaid and other current assets” in the condensed consolidated balance sheets.

The following tables summarize the gains or losses related to our cash flow hedges and derivatives not designated as cash flow hedging instruments.

Derivatives in Cash Flow Hedging Relationships

(in Millions)			Total Foreign Exchange Contracts
Accumulated other comprehensive income, net of tax as of December 31, 2023			$	—
Unrealized hedging gains, net of tax			0.2
Total derivatives instruments impact on comprehensive income, net of tax			0.2
Accumulated other comprehensive income, net of tax as of March 31, 2024			$	0.2

(in Millions)			Total Foreign Exchange Contracts
Accumulated other comprehensive income, net of tax as of December 31, 2022			$	—
Unrealized hedging gains, net of tax			0.2
Total derivatives instruments impact on comprehensive income, net of tax			0.2
Accumulated other comprehensive income, net of tax as of March 31, 2023			$	0.2

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Derivatives Not Designated as Cash Flow Hedging Instruments

			Location of Gain or (Loss) Recognized in Income on Derivatives																		Amount of Pre-tax Gain or (Loss)  Recognized in Income on Derivatives (1)
															Three Months Ended March 31,
(in Millions)																					2024						2023
Foreign Exchange contracts			Other gain																		$	13.9					$	—
Foreign Exchange contracts			Cost of sales																		(3.3)						2.1
Total																					$	10.6					$	2.1

____________________

1.Amounts represent the gain or loss on the derivative instrument offset by the gain or loss on the hedged item.

Fair Value Measurements

Recurring Fair Value Measurements

The following tables present our fair-value hierarchy for those assets and liabilities measured at fair-value on a recurring basis in our condensed consolidated balance sheets.

(in Millions)			March 31, 2024						Quoted Prices in Active Markets for Identical Assets (Level 1)						Significant Other Observable Inputs (Level 2)						Significant Unobservable Inputs (Level 3)
Assets
Investments in deferred compensation plan (1)			$	6.0					$	6.0					$	—					$	—
JEMSE Receivable			5.5						—						—						5.5
Equity securities (2)			2.5						2.5						—						—
Derivatives – Foreign exchange			0.2						—						0.2						—
Total Assets			$	14.2					$	8.5					$	0.2					$	5.5
Liabilities
Deferred compensation plan obligation (3)			$	7.2					$	7.2					$	—					$	—
Total Liabilities			$	7.2					$	7.2					$	—					$	—

 

(in Millions)			December 31, 2023						Quoted Prices in Active Markets for Identical Assets (Level 1)						Significant Other Observable Inputs (Level 2)						Significant Unobservable Inputs (Level 3)
Assets
Investments in deferred compensation plan (1)			$	4.1					$	4.1					$	—					—
Total Assets			$	4.1					$	4.1					$	—					$	—
Liabilities
Deferred compensation plan obligation (3)			$	6.7					$	6.7					$	—					$	—
Total Liabilities (4)			$	6.7					$	6.7					$	—					$	—

____________________

1.Balance is included in “Investments” in the condensed consolidated balance sheets. Arcadium NQSP investments in Arcadium ordinary shares are recorded as "Treasury shares" in the condensed consolidated balance sheets and carried at historical cost. Mark-to-market gains of $0.8 million were recorded for the three months ended March 31, 2024 and mark-to-market losses of $0.2 million were recorded for the three months ended March 31, 2023, related to the Arcadium ordinary shares. The mark-to-market gains and losses were recorded

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in "Selling, general and administrative expenses" in the condensed consolidated statements of operations, with a corresponding offset to the deferred compensation plan obligation in the condensed consolidated balance sheets.

2.Mark-to-market gains and losses are recorded to "Other gain/loss" in the condensed consolidated statement of operations.

3.Balance is included in “Other long-term liabilities” in the condensed consolidated balance sheets.

Contingencies

We are a party to various legal proceedings, certain of these matters are discussed below. Arcadium records liabilities for estimated losses from contingencies when information available indicates that a loss is probable and the amount of the loss, or range of loss, can be reasonably estimated. As additional information becomes available, management adjusts its assessments and estimates. Legal costs are expensed as incurred.

In addition to the legal proceedings noted below, we have certain contingent liabilities arising in the ordinary course of business. Some of these contingencies are known but are so preliminary that the merits cannot be determined, or if more advanced, are not deemed material based on current knowledge; and some are unknown - for example, claims with respect to which we have no notice or claims which may arise in the future from products sold, guarantees or warranties made, or indemnities provided. Therefore, we are unable to develop a reasonable estimate of our potential exposure of loss for these contingencies, either individually or in the aggregate, at this time. There can be no assurance that the outcome of these contingencies will be favorable, and adverse results in certain of these contingencies could have a material adverse effect on the consolidated financial position, results of operations in any one reporting period, or liquidity.

Argentine Customs & Tax Authority Matters

Minera del Altiplano SA, our subsidiary in Argentina ("MdA"), has received notices from the Argentine Customs Authorities that they are conducting customs audits in Salta (for 2015 to 2019, 2021 and 2022), Rosario (for 2016 and 2017), Buenos Aires and Ezeiza (for 2018, 2019, 2021 and 2022) regarding the export of lithium carbonate by MdA from each of those locations. See Note 20 for more information about the payment the Company made in June 2023 for export duties and interest claimed by the Customs Authorities of Buenos Aires, Ezeiza and Salta related to exports made between the years 2018 – 2022. MdA was also notified from the Argentine Tax Authority of the start of transfer pricing audits for the periods 2017 and 2018.

SDJ SA, our subsidiary in Argentina, received notification from Jujuy provincial tax authority regarding a royalty adjustment in favor of the Province for the periods 2021 and 2022. SDJ SA was also notified by the Argentine Tax Authority of the start of a transfer pricing audit for the period of 2018.

A range of reasonably possible liabilities, if any, cannot be currently estimated by the Company.

In January, 2023, the Argentina Ministry of Economy issued a resolution to cancel an export rebate regime relating to lithium products, which was followed by Presidential Decree No. 57/2023 in February, 2023. The Presidential Decree prospectively cancels all export rebates for lithium products. Prior to the Presidential Decree, MdA had the right to collect 4% of the FOB value for exported products (which consisted of the "La Puna" rebate which was 2.5% and the "Export" rebate which was 1.5%). In October 2023 by Presidential Decree No. 557/2023 the Export rebate of 1.5% was reinstated. Subsequent to the Presidential Decree entering into force on October 26, 2023 MdA is entitled to the 1.5% rebate/refund on FOB value of its exported products. As of March 31, 2024, MdA has a receivable of approximately $4.5 million USD which is still valid and remains in force after the Presidential Decrees.

Australia Tax Matters

We were informed on April 16, 2024 that the Australian Taxation Office will be performing a combined assurance review of Allkem Limited and its Australian subsidiaries for the period of July 1, 2019 to June 30, 2023.

Leases

All of our leases are operating leases as of March 31, 2024 and December 31, 2023. We have operating leases for corporate offices, manufacturing facilities, and land. Our leases have remaining lease terms of two to twenty-seven years.

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The Company assumed an ROU asset and corresponding lease liability of $53.4 million in the Allkem Livent Merger, all of which are accounted for as operating leases.

Quantitative disclosures about our leases are summarized in the table below.

									Three Months Ended March 31,
(in Millions, except for weighted-average amounts)															2024						2023
Lease Cost
Operating lease cost															$	4.3					$	0.3
Short-term lease cost															0.1						0.1
Total lease cost (1)															$	4.4					$	0.4
Other information
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for operating leases															$	4.4					$	0.3

__________________________

1.Lease expense is classified as "Selling, general and administrative expenses" in our condensed consolidated statements of operations.

As of March 31, 2024, our operating leases had a weighted average remaining lease term of 7.9 years and a weighted average discount rate of 8.4%.

The table below presents a maturity analysis of our operating lease liabilities for each of the next five years and a total of the amounts for the remaining years.

(in Millions)						Undiscounted cash flows
Remainder of 2024						$	11.9
2025						10.0
2026						9.1
2027						8.4
2028						8.0
Thereafter						31.0
Total future minimum lease payments						78.4
Less: Imputed interest						(23.3)
Total						$	55.1

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The following tables present details of prepaid and other current assets, other assets, accrued and other current liabilities, and other long-term liabilities as presented on the condensed consolidated balance sheets:

(in Millions)			March 31, 2024						December 31, 2023
Prepaid and other current assets
Tax related items			$	71.8					$	29.5
Prepaid expenses			30.8						16.9
Argentina government receivable (1)			9.8						7.9
Other receivables			47.6						28.2
Bank Acceptance Drafts (2)			0.6						—
Derivative assets (Note 17)			0.2						—
Other current assets			4.9						3.9
Total			$	165.7					$	86.4

(in Millions)			March 31, 2024						December 31, 2023
Other assets
Argentina government receivable (1), (3)			$	80.4					$	71.3
Advance to contract manufacturers (4)			26.8						27.6
Long-term semi-finished goods inventory			192.2						1.0
Tax related items			4.2						4.0
Capitalized software, net			1.7						1.1
Investment in transit - Nemaska Lithium (5)			39.1						—
Other assets			97.7						22.7
Total			$	442.1					$	127.7

_________________

1.We have various subsidiaries that conduct business in Argentina. As of March 31, 2024 and December 31, 2023, $39.4 million and $38.8 million, respectively, of outstanding receivables due from the Argentina government, which primarily represent export tax and export rebate receivables, was denominated in U.S. dollars. A recent judicial decision relating to the U.S. dollar-denominated export tax receivable portion ($34.8 million) permits the Argentina government to reimburse us in Argentine pesos at the historical foreign exchange rate applicable at each past payment date, adjusted by a bank deposit interest rate. While Arcadium filed an appeal on November 6, 2023 and believes it has valid defenses on the technical merits, the ultimate resolution of this matter could result in a possible loss of up to $34.3 million. We continually review the recoverability of all outstanding receivables by analyzing historical experience, current collection trends and regional business and political factors among other factors.

2.Bank Acceptance Drafts are a common Chinese finance note used to settle trade transactions. The Company accepts these notes from Chinese customers based on criteria intended to ensure collectability and limit working capital usage.

3.In June 2023, the Company decided to pay $21.7 million for the export duties and interest claimed by the Customs Authorities of Buenos Aires, Ezeiza and Salta related to exports made between the years 2018 – 2022 registered in those locations. This payment stops the accrual of any further interest. It was a deposit made under protest and was not an admission of any of the claims made by the Customs Authorities or a waiver of any of the Company's defenses, including recovery of the deposit plus interest. The cases remain in discussion. See Note 19 for more information.

4.We record deferred charges for certain contract manufacturing agreements which we amortize over the term of the underlying contract.

5.Represents the Company's cash contributed to Nemaska Lithium in the first quarter of 2024 which, due to quarter-lag reporting, are not yet recorded in our consolidation of Nemaska. The balance is recorded to Other assets - noncurrent because the cash is expected to be used by Nemaska primarily for capital expenditures. See Note 9 for details.

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(in Millions)			March 31, 2024						December 31, 2023
Accrued and other current liabilities
Accrued payroll			$	32.4					$	31.2
Retirement liability - 401k			5.0						3.2
Environmental reserves, current			2.6						0.5
Severance			5.6						1.7
Accrued investment in unconsolidated affiliates			—						27.0
Other accrued and other current liabilities (1)			81.0						73.2
Total			$	126.6					$	136.8

(in Millions)			March 31, 2024						December 31, 2023
Other long-term liabilities
Deferred compensation plan obligation			$	7.2					$	6.7
Contingencies related to uncertain tax positions (2)			15.8						6.2
Self-insurance reserves			1.1						1.1
Asset retirement obligations			12.5						3.7
Other long-term liabilities			56.6						3.6
Total			$	93.2					$	21.3

____________________

1.Amounts primarily include accrued capital expenditures related to our expansion projects.

2.As of March 31, 2024, we have recorded a liability for uncertain tax positions of $15.4 million and a $0.4 million indemnification liability where the offsetting uncertain tax position is with FMC, per the tax matters agreement.

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Sara Ponessa, the Company’s General Counsel and Secretary, adopted a trading plan that is intended to satisfy the affirmative defense of Rule 10b5-1(c) and complies with the requirements of Rule 10b5-1 (the “Ponessa Sales Plan”) to sell an aggregate of 64,161 shares upon the exercise of share options held by Ms. Ponessa under the Company’s share compensation plans and 70,000 shares from shares held on deposit in Ms. Ponessa's account. The Ponessa Sales Plan was adopted on March 4, 2024, with sales commencing under the Ponessa Sales Plan on June 5, 2024. The Ponessa Sales Plan terminates on the earliest to occur of (a) the close of business on January 15, 2025; (b) execution of all trades or expiration of all of the orders relating to such trades as specified in the Ponessa Sales Plan; (c) the date that the broker receives notice of liquidation, dissolution, bankruptcy, insolvency, or death of Ms. Ponessa; (d) when the broker receives notice from Ms. Ponessa of her termination of the Ponessa Sales Plan; (e) when the broker determines, in its sole discretion, that the Ponessa Sales Plan has been terminated, including, without limitation, where the broker determines there has been a modification or change to the Ponessa Sales Plan that constitutes the termination of the Ponessa Sales Plan; (f) the date the broker notifies Ms. Ponessa of the broker’s termination of the Ponessa Sales Plan due to Ms. Ponessa’s breach of any of the terms of the Ponessa Sales Plan or in the event that Ms. Ponessa trades shares outside of the Ponessa Sales Plan; or (g) where the broker exercises any other termination right it may have under the Ponessa Sales Plan.

Paul Graves, the Company’s President, Chief Executive Officer and Director, adopted a trading plan that is intended to satisfy the affirmative defense of Rule 10b5-1(c) and complies with the requirements of Rule 10b5-1 (the “Graves Sales Plan”) to sell an aggregate of 234,038 shares upon the exercise of share options held by Mr. Graves under the Company’s share compensation plans and 100,000 shares from shares held on deposit in Mr. Graves' account. The Graves Sales Plan was adopted on March 27, 2024, with sales commencing under the Graves Sales Plan on July 1, 2024. The Graves Sales Plan terminates on the earliest to occur of (a) the close of business on December 31, 2025; (b) execution of all trades or expiration of all of the orders relating to such trades as specified in the Graves Sales Plan; (c) the date that the broker receives notice of liquidation, dissolution, bankruptcy, insolvency, or death of Mr. Graves; (d) when the broker receives notice from Mr. Graves of his termination of the Graves Sales Plan; (e) when the broker determines, in its sole discretion, that the Graves Sales Plan has been terminated, including, without limitation, where the broker determines there has been a modification or change to the Graves Sales Plan that constitutes the termination of the Graves Sales Plan; (f) the date the broker notifies Mr. Graves of the broker’s termination of the Graves Sales Plan due to Mr. Grave’s breach of any of the terms of the Graves Sales Plan or in the event that Mr. Graves trades shares outside of the Graves Sales Plan; or (g) where the broker exercises any other termination right it may have under the Graves Sales Plan.

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v3.24.1.1.u2

Cover - shares	3 Months Ended
	Mar. 31, 2024	May 08, 2024
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-38694
Entity Registrant Name	ARCADIUM LITHIUM PLC
Entity Incorporation, State or Country Code	Y9
Entity Tax Identification Number	98-1737136
Entity Address, Address Line One	1818 Market Street
Entity Address, Address Line Two	Suite 2550
Entity Address, City or Town	Philadelphia
Entity Address, State or Province	PA
Entity Address, Country	US
Entity Address, Postal Zip Code	19103
City Area Code	215
Local Phone Number	299-5900
Title of 12(b) Security	Ordinary Shares, par value $1.00 per share
Trading Symbol	ALTM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		1,075,191,645
Entity Central Index Key	0001977303
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false
Other Address
Entity Information [Line Items]
Entity Address, Address Line One	Suite 12, Gateway Hub
Entity Address, Address Line Two	Shannon Airport House
Entity Address, City or Town	Shannon, Co. Clare
Entity Address, Country	IE
Entity Address, Postal Zip Code	V14 E370
City Area Code	353-1
Local Phone Number	6875238

v3.24.1.1.u2

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	[1]
Income Statement [Abstract]
Revenue	$ 261.2	$ 253.5
Cost of sales	116.8	87.5
Gross margin	144.4	166.0
Selling, general and administrative expenses	39.9	16.3
Research and development expenses	1.1	1.0
Restructuring and other charges	83.6	1.9
Total costs and expenses	241.4	106.7
Income from operations before equity in net loss of unconsolidated affiliate, interest income, net, loss on debt extinguishment and other gain	19.8	146.8
Equity in net loss of unconsolidated affiliate	0.0	8.1	[2]
Interest income, net	(11.0)	0.0
Loss on debt extinguishment	0.2	0.0	[2]
Other gain	(43.1)	0.0
Income from operations before income taxes	73.7	138.7
Income tax expense	53.8	23.9
Net income	19.9	114.8	[2],[3],[4]
Net income attributable to noncontrolling interests	4.3	0.0
Net income attributable to Arcadium Lithium plc	$ 15.6	$ 114.8
Basic earnings per ordinary share (in dollars per share)	$ 0.01	$ 0.27
Diluted earnings per ordinary share (in dollars per share)	$ 0.01	$ 0.23
Weighted average ordinary shares outstanding - basic (in shares)	1,053.4	432.0
Weighted average ordinary shares outstanding - diluted (in shares)	1,122.1	503.3
[1] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem. [2] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem. [3] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. [4] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem.

v3.24.1.1.u2

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical)	Jan. 04, 2024	Mar. 31, 2023
Exchange ratio		2.406
Allkem Livent Merger
Exchange ratio	2.406

v3.24.1.1.u2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS)/INCOME - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	[4]
Statement of Comprehensive Income [Abstract]
Net income	$ 19.9	$ 114.8	[1],[2],[3]
Foreign currency adjustments:
Foreign currency translation loss/(income) arising during the period	(20.2)	1.5
Foreign currency translation adjustments	(20.2)	1.5	[3]
Derivative instruments:
Unrealized hedging gains, net of tax of less than zero and $0.1	0.2	0.2	[3]
Total derivative instruments	0.2	0.2
Other comprehensive (loss)/income, net of tax	(20.0)	1.7
Comprehensive (loss)/income	(0.1)	116.5
Comprehensive income attributable to noncontrolling interests	4.3	0.0
Comprehensive (loss)/income attributable to Arcadium Lithium plc	$ (4.4)	$ 116.5
[1] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem. [2] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem. [3] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. [4] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem.

v3.24.1.1.u2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS)/INCOME (Parenthetical) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Unrealized hedging losses, tax	$ 0	$ 100,000

v3.24.1.1.u2

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	[1]
Current assets
Cash and cash equivalents	$ 472.7	$ 237.6
Trade receivables, net of allowance of approximately $0.1 in 2024 and $0.3 in 2023	93.5	106.7
Inventories, net	328.8	217.5
Prepaid and other current assets	165.7	86.4
Total current assets	1,060.7	648.2
Investments	38.6	34.8
Property, plant and equipment, net of accumulated depreciation of $279.1 in 2024 and $269.1 in 2023	6,793.7	2,237.1
Goodwill	1,309.9	120.7
Other intangibles, net	56.8	53.4
Deferred income taxes	35.9	1.4
Right of use assets - operating leases, net	55.6	6.8
Other assets	442.1	127.7
Total assets	9,793.3	3,230.1
Current liabilities
Short-term debt and current portion of long-term debt	80.6	2.4
Accounts payable, trade and other	197.2	115.4
Accrued and other liabilities	126.6	136.8
Contract liability - short-term	30.6	4.4
Operating lease liabilities - current	10.2	1.3
Income taxes	89.3	8.3
Total current liabilities	534.5	268.6
Long-term debt	502.7	299.6
Operating lease liabilities - long-term	44.9	5.6
Environmental liabilities	7.5	7.0
Deferred income taxes	1,429.9	126.4
Contract liability - long-term	218.3	217.8
Other long-term liabilities	93.2	21.3
Commitments and contingent liabilities (Note 19)	0.0	0.0
Total current and long-term liabilities	2,831.0	946.3
Equity
Ordinary shares; $1.00 par value; 5,000,000,000 shares authorized; 1,075,070,500 and 433,059,946 shares issued; 1,074,807,292 and 432,796,277 outstanding as of March 31, 2024 and December 31, 2023, respectively	0.1	0.1
Capital in excess of par value of ordinary shares	5,574.0	1,170.4
Retained earnings	680.1	664.5
Accumulated other comprehensive loss	(69.8)	(49.8)
Treasury shares, ordinary, at cost; 263,208 and 263,669 shares as of March 31, 2024 and December 31, 2023, respectively	(1.0)	(1.0)
Total Arcadium Lithium plc shareholders’ equity	6,183.4	1,784.2
Noncontrolling interests	778.9	499.6
Total equity	6,962.3	2,283.8
Total liabilities and equity	$ 9,793.3	$ 3,230.1
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Current assets
Allowance for trade receivables	$ 0.1	$ 0.3
Accumulated depreciation	$ 279.1	$ 269.1
Equity
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common stock, shares authorized (in shares)	5,000,000,000	5,000,000,000
Common stock, shares issued (in shares)	1,075,070,500	433,059,946
Common stock, outstanding (in shares)	1,074,807,292	432,796,277
Treasury stock, shares (in shares)	263,208	263,669

v3.24.1.1.u2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	[1]
Cash (used in)/provided by operating activities:
Net income		$ 19.9	$ 114.8	[2],[3],[4]
Adjustments to reconcile net income to cash (used in)/provided by operating activities:
Depreciation and amortization		17.2	6.8
Restructuring and other charges		(43.1)	0.6
Deferred income taxes		(20.9)	1.4
Share-based compensation		2.2	1.9
Change in investments in trust fund securities		(0.8)	0.2
Loss on debt extinguishment		0.2	0.0	[2]
Equity in net loss of unconsolidated affiliate		0.0	8.1	[2]
Other gain, Blue Chip Swap		(29.6)	0.0
Other non-cash adjustments		2.7	(0.4)
Changes in operating assets and liabilities:
Trade receivables, net		78.0	30.3
Inventories		8.4	(31.0)
Accounts payable, trade and other		(85.3)	(17.8)
Changes in deferred compensation		1.3	0.9
Contract liability - short-term		26.2	(13.0)
Income taxes		1.7	14.3
Change in prepaid and other current assets and other assets		(84.0)	(8.3)
Change in accrued and other current liabilities and other long-term liabilities		53.1	(5.9)
Cash (used in)/provided by operating activities		(52.8)	102.9
Cash provided by/(used in) investing activities:
Capital expenditures	[5]	(312.3)	(73.5)
Investments in Arcadium NQSP securities		(0.9)	(0.7)
Proceeds from Blue Chip Swap, net of purchases		29.6	0.0
Acquired cash & cash equivalents - Allkem Livent Merger		681.4	0.0
Investments in unconsolidated affiliates (3)	[6]	(27.0)	(20.2)
Other investing activities (4)		(44.6)	(3.7)
Cash provided by/(used in) investing activities		326.2	(98.1)
Cash used in financing activities:
Proceeds from Revolving Credit Facility		88.0	0.0
Repayments of Revolving Credit Facility		(88.0)	0.0
Payments of financing fees		(3.5)	0.0
Repayments of Project Loan Facility		(18.1)	0.0
Payments of financing fees		0.0	(0.1)
Cash used in financing activities		(21.6)	(0.1)
Effect of exchange rate changes on cash and cash equivalents		(16.7)	0.4
Increase in cash and cash equivalents		235.1	5.1
Cash and cash equivalents, beginning of period		237.6	189.0
Cash and cash equivalents, end of period		472.7	194.1
Supplemental Disclosure for Cash Flow:
Cash payments for income taxes, net of refunds		33.7	1.9
Cash payments for interest	[5]	6.6	5.5
Cash payments for Restructuring and other charges		126.7	1.3
Accrued capital expenditures		180.5	15.3
Operating lease right-of-use assets and lease liabilities recorded for ASC 842		$ 0.0	$ 1.2
[1] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem. [2] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem. [3] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. [4] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem. [5] For the three months ended March 31, 2024 and 2023, $6.3 million and $3.9 million of interest expense was capitalized, respectively. [6] On October 18, 2023 we began consolidating Nemaska Lithium, see Note 9 for details. 4.Includes the Company's $39.1 million cash contributed to Nemaska Lithium in the first quarter of 2024 which, due to quarter-lag reporting, is not yet recorded in our consolidation of Nemaska. The balance is recorded to Other assets - noncurrent because the cash is expected to be used by Nemaska primarily for capital expenditures. See Note 9 for details.

v3.24.1.1.u2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Cash Flows [Abstract]
Interest expense capitalized	$ 6.3	$ 3.9

v3.24.1.1.u2

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions		Total		Ordinary Shares, $1.00 Per Share Par Value	Capital In Excess of Par	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Shares	Non-controlling Interest
Beginning balance at Dec. 31, 2022	[1]	$ 1,443.0		$ 0.1	$ 1,160.4	$ 334.4	$ (51.0)	$ (0.9)	$ 0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	[1]	114.8	[2],[3],[4]			114.8
Share compensation plans	[1]	1.9			1.9
Shares withheld for taxes - ordinary share issuances	[1]	(0.5)			(0.5)
Exercise of share options	[1]	0.1			0.1
Net hedging gains, net of income tax	[1]	0.2	[4]				0.2
Foreign currency translation adjustments	[1]	1.5	[4]				1.5
Ending balance at Mar. 31, 2023	[1]	1,561.0		0.1	1,161.9	449.2	(49.3)	(0.9)	0.0
Beginning balance at Dec. 31, 2023		2,283.8	[5]	0.1	1,170.4	664.5	(49.8)	(1.0)	499.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		19.9				15.6			4.3
Allkem Livent Merger		4,665.4			4,390.4				275.0
Share compensation plans		15.8			15.8
Shares withheld for taxes - ordinary share issuances		(2.6)			(2.6)
Net hedging gains, net of income tax		0.2					0.2
Foreign currency translation adjustments		(20.2)					(20.2)
Ending balance at Mar. 31, 2024		$ 6,962.3		$ 0.1	$ 5,574.0	$ 680.1	$ (69.8)	$ (1.0)	$ 778.9
[1] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. [2] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem. [3] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem. [4] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem. [5] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	Mar. 31, 2024	Jan. 04, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Statement of Stockholders' Equity [Abstract]
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00

v3.24.1.1.u2

Description of the Business	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business	Description of the Business Background and Nature of Operations Arcadium Lithium plc ("Arcadium", "Arcadium Lithium", "we", "us", "Company" or "our") is a public limited company incorporated under the laws of the Bailiwick of Jersey. On January 4, 2024, Arcadium Lithium completed the previously announced Allkem Livent Merger by which Livent Corporation, a Delaware corporation ("Livent"), and Allkem Limited, an Australian company limited by shares ("Allkem"), became wholly owned subsidiaries of Arcadium Lithium. On January 4, 2024, the Company's shares started trading on the New York Stock Exchange under the trading symbol ALTM. See Note 4, Allkem Livent Merger for further details. While Arcadium Lithium is a newly formed company from the merger of Allkem and Livent, our company has a rich heritage of innovation and a long, proven history of producing performance lithium compounds in a safe and sustainable manner. We are vertically integrated, with a global footprint and industry-leading end-to-end capabilities across lithium production including hard-rock mining, conventional pond-based brine extraction, direct lithium brine extraction and lithium chemicals manufacturing. Our lithium asset portfolio, consisting of both operating assets and development projects, provides us with global reach, scale, and product flexibility. Today we have operating resources in Argentina and Australia and downstream conversion assets in the U.S., China, Japan, and the U.K. We also have multiple ongoing development projects in Argentina (greenfield and brownfield) and Canada (greenfield) to increase production capabilities and our ability to meet the needs of customers around the world. In the U.S., we operate the only integrated mine-to-metal production facility in the Western Hemisphere for high purity lithium metal, a core component of next generation battery technologies. We manufacture a wide range of lithium products, including battery-grade lithium hydroxide, battery-grade lithium carbonate, spodumene, and other specialty chemicals such as butyllithium and high purity lithium metal. Our products are used in various performance applications, including lithium-based batteries, specialty polymers and pharmaceutical products and chemical synthesis applications.

v3.24.1.1.u2

Significant Accounting Policies and Related Financial Information	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Significant Accounting Policies and Related Financial Information	Significant Accounting Policies and Related Financial Information In this Form 10-Q, the results of the Company as of and for the three months ended March 31, 2024 include the operations and financial position of Allkem. Because Arcadium Lithium plc is the successor company to Livent in the Allkem Livent Merger, we are presenting the results of predecessor Livent’s operations for the three months ended March 31, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. Refer to Note 4 for further information related to the Allkem Livent Merger. The accompanying condensed consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission ("SEC") for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. GAAP have been condensed or omitted from these interim financial statements. The financial statements included in this report reflect all normal and recurring adjustments which, in the opinion of management, are necessary for a fair presentation of our condensed consolidated balance sheets as of March 31, 2024 and December 31, 2023, the condensed consolidated results of operations, the condensed consolidated statement of comprehensive income and the condensed consolidated statement of changes in equity for the three months ended March 31, 2024 and 2023, and the condensed consolidated cash flows for the three months ended March 31, 2024 and 2023. All intercompany transactions and balances have been eliminated in consolidation. For entities that we control, but own less than 100%, we record the minority ownership as noncontrolling interest. The unaudited results of operations for the interim periods reported are not necessarily indicative of results to be expected for the full year. These statements, therefore, should be read in conjunction with the annual consolidated financial statements and related notes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 (the "2023 Annual Report on Form 10-K"). Segment Information In January 2024, Arcadium Lithium completed the Allkem Livent Merger. See Note 4, Allkem Livent Merger for further details. Following the closing of the Allkem Livent Merger, we currently operate as one reportable segment based on the commonalities among our products and services. As integration evolves, we will continue to assess this determination. Revenue Recognition Revenue from product sales is recognized when we satisfy a performance obligation by transferring the promised goods to a customer, that is, when control of the good transfers to the customer. Payment terms generally range from 20 to 180 days. In determining when the control of goods is transferred, we typically assess, among other things, the transfer of title and risk of loss and the shipping terms of the contract. We record amounts billed for shipping and handling fees as revenue. Costs incurred for shipping and handling are recorded in cost of sales. When we perform shipping and handling activities after the transfer of control to the customer (e.g., when control transfers prior to delivery), they are considered fulfillment activities, and accordingly, the costs are accrued to cost of sales when the related revenue is recognized. Amounts billed for sales and use taxes, VAT, and certain excise and other specific transactional taxes imposed on revenue-producing transactions are presented on a net basis and excluded from revenue in the condensed consolidated statements of operations. We record a liability until remitted to the respective taxing authority. We satisfy our obligations by transferring goods and services in exchange for consideration from customers. The timing of performance sometimes differs from the timing the associated consideration is received from the customer, thus resulting in the recognition of a contract asset or liability. These may arise from provisional pricing within certain of our customer contracts, or if the customer’s payment of consideration is received prior to completion of our related performance obligation. Provisional pricing results in variable consideration which we estimate by using an expected value method taking into account all information that is reasonably available including publicly available pricing forecasts. We only include variable consideration within the transaction price to the extent that it is probable that a significant reversal in the amount of revenue recognized will not occur. Equity method investments We stop applying the equity method when we have reduced the value of our equity method investment, commitments and additional investments (i.e., loans or advances) in the investee to zero. If the investee subsequently reports net income, we resume applying the equity method when our share of that net income is equal to the suspended losses (i.e., our share of the investee's net losses not previously recognized). If facts and circumstances indicate that a decrease in value of the investment has occurred that is other than temporary, we recognize an impairment loss equal to an amount by which the carrying amount exceeds the fair value of the equity method investment. There were no impairments during the three months ended March 31, 2024. Goodwill The Company accounts for goodwill and other intangibles acquired in a business combination in conformity with current accounting guidance that requires that goodwill and indefinite-lived intangible assets not be amortized. Under the guidance, goodwill is tested for impairment by comparing the estimated fair value of reporting units to the related carrying value. Reporting units are either operating business segments or one level below operating business segments for which discrete financial information is available and for which operating results are regularly reviewed by the business management. In applying the goodwill impairment test, a qualitative test ("Step 0") is initially performed, under which qualitative factors are assessed to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. Qualitative factors may include, but are not limited to, economic conditions, industry and market considerations, cost factors, overall financial performance of the reporting units and other entity and reporting unit specific events. If after assessing these qualitative factors, it is determined that it is "more-likely-than-not" that the fair value of the reporting unit is less than the carrying value, a quantitative test ("Step 1") is performed. During Step 1, the fair value is estimated using a discounted cash flow model. Mine Development Costs Mine development costs include: a) exploration and evaluation ("E&E") expenditures incurred during the search for mineral resources as well as the determination of the technical feasibility and commercial viability of extracting the mineral resource; and b) stripping costs of removing overburden and waste materials to access the mineral body at an open pit mine. The Company capitalizes E&E expenditures to PP&E under a successful efforts basis when proven and probable reserves are established for the sites where E&E activities are being performed. E&E assets recognized as part of business combinations are also capitalized. All other E&E expenditures are expensed. Stripping costs incurred prior to the production phase are capitalized to PP&E during the development of an open pit mine. When multiple open pits exist at a mining complex utilizing common processing facilities, such pre-production stripping costs are capitalized at each pit. The removal, production, and sale of de minimis saleable materials may occur during the development phase of an open pit mine and are assigned incremental mining costs related to the removal of that material. The production phase of an open pit mine commences when saleable minerals, beyond a de minimis amount, are produced. Stripping costs incurred during the production phase of a mine are variable production costs that are included as a component of inventory to be recognized in Cost of Sales in the same period as the revenue from sale of that inventory. Capitalized mine development costs are amortized using the units-of-production method based on estimated recoverable minerals in proven and probable reserves, and are amortized over the estimated life of the mineral body. Mineral Interests Mineral interests include acquired interests in production, development and exploration stage properties. Mineral interests are capitalized at their fair value at the acquisition date, either as an individual asset purchase or as part of a business combination. Mineral interests in the development and exploration stage are not amortized until the underlying property is converted to the production stage, at which point the mineral interests are amortized over the estimated recoverable proven and probable reserves using a units-of-production method. Asset Retirement Obligations The Company accounts for asset retirement obligations ("AROs") in accordance with ASC 410-20, Asset Retirement Obligations "ASC 410-20". We record AROs at present value at the time the liability is incurred if we can reasonably estimate the settlement date. The associated AROs are capitalized as part of the carrying amount of related long-lived assets. In future periods, the liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. We also adjust the liability for changes resulting from the passage of time and/or revisions to the timing or the amount of the original estimate. Upon retirement of the long-lived asset, we either settle the obligation for its recorded amount. See Note 13, for details. The carrying amounts of the AROs as of March 31, 2024 and December 31, 2023 was $12.5 million and $3.7 million, respectively. These amounts are included in "Accrued and other current liabilities" and "Other long-term liabilities" in our condensed consolidated balance sheets. Blue Chip Swap Our wholly owned subsidiaries in Argentina use the U.S. dollar as their functional currency. Argentina peso-denominated monetary assets and liabilities are remeasured at each balance sheet date to the official currency exchange rate then in effect which represents the exchange rate available for external commerce (import payments and export collections) and financial payments, with currency remeasurement and other transaction gains and losses recognized in earnings. In September 2019, the President of Argentina reinstituted exchange controls restricting foreign currency purchases in an attempt to stabilize Argentina’s financial markets. As a result, a legal trading mechanism known as the Blue Chip Swap emerged in Argentina for all individuals or entities to transfer U.S. dollars out of and into Argentina. The Blue Chip Swap rate is the implicit exchange rate resulting from the Blue Chip Swap transaction. In 2023, the Blue Chip Swap rate diverged significantly from Argentina’s official rate due to economic conditions, but the gap has narrowed considerably in 2024 due to reforms. In the first quarter of 2024, U.S. dollars were transferred into Argentina through the Blue Chip Swap method whereby we realized a gain from the purchase in U.S. dollars and sale in Argentina pesos of Argentina Sovereign U.S. dollar-denominated bonds. The gain of $29.6 million for the three months ended March 31, 2024 was recorded to Other gain in our condensed consolidated statements of operations.

v3.24.1.1.u2

Recently Issued and Adopted Accounting Pronouncements and Regulatory Items	3 Months Ended
	Mar. 31, 2024
Accounting Policies [Abstract]
Recently Issued and Adopted Accounting Pronouncements and Regulatory Items	Recently Issued and Adopted Accounting Pronouncements and Regulatory Items In December 2023, the Financial Accounting Standard Board ("FASB") issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU enhances existing income tax disclosures to better assess how an entity's operation and related tax risks, tax planning, and operational opportunities affect its tax rate and prospects for future cash flows. The ASU is effective for annual periods beginning after December 15, 2024. We are currently evaluating the effect the guidance will have on our condensed consolidated financial statements. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280). This ASU improves reportable segment disclosure requirements, primarily through enhanced disclosures related to significant segment expenses. The ASU is effective for annual periods beginning after December 15, 2023, and interim periods beginning after December 15, 2024. We are currently evaluating the effect the guidance will have on our condensed consolidated financial statements.

v3.24.1.1.u2

Allkem Livent Merger	3 Months Ended
	Mar. 31, 2024
Business Combination and Asset Acquisition [Abstract]
Allkem Livent Merger	Allkem Livent Merger On January 4, 2024 (the "Acquisition Date") Arcadium completed the previously announced Allkem Livent Merger by and among Livent Corporation, a Delaware corporation ("Livent"), Allkem Limited, an Australian public company ("Allkem"), Arcadium Lithium plc, a public limited company incorporated under the laws of the Bailiwick of Jersey ("Arcadium"), Lightning-A Merger Sub, Inc. ("Merger Sub"), and Arcadium Lithium Intermediate IRL Limited, a private company limited by shares and incorporated and registered in Ireland ("Irish IntermediateCo"). The transaction was consummated by way of (a) a scheme of arrangement under Australian law, pursuant to which each issued, fully paid ordinary share of Allkem held by Allkem shareholders was exchanged for either one Arcadium Lithium CHESS Depositary Instrument (a "CDI") quoted on the Australian Stock Exchange (each CDI representing a beneficial ownership interest in one Arcadium ordinary share), or one Arcadium ordinary share (par value $1.00 per share) and (b) a merger, whereby Merger Sub, a wholly owned subsidiary of Irish IntermediateCo (a direct wholly owned subsidiary of Arcadium) merged with and into Livent, with Livent as the surviving entity. Each share of Livent common stock, par value $0.001 per share (each, a "Livent Share"), was converted into the right to receive 2.406 Arcadium ordinary shares. Pursuant to the Allkem Livent Merger, 433,156,855 Arcadium ordinary shares (including 96,909 related to accelerated PRSU awards) were issued to former Livent stockholders and 641,337,840 Arcadium ordinary shares (comprising 98,725,616 Arcadium ordinary shares and 542,612,224 CDIs in respect of Arcadium ordinary shares) were issued to former Allkem shareholders. The Acquisition Date fair value of consideration transferred consisted of the following: (in millions) Amount Consideration: Fair value of Arcadium ordinary shares issued to Allkem shareholders $ 4,385.6  Fair value of converted Allkem performance rights attributable to pre-combination service 4.8  Total consideration $ 4,390.4  The Allkem Livent Merger meets the criteria to be accounted for as a business combination and is accounted for using the acquisition method of accounting with Livent being treated as the accounting acquirer. Under the acquisition method of accounting, the assets and liabilities of Allkem and its subsidiaries are recorded at their respective fair values as of the date of completion of the Allkem Livent Merger and the difference between the fair value of the consideration paid for the acquired entity and fair value of the net assets acquired is recorded as goodwill. The fair value of the assets, liabilities and noncontrolling interest of Allkem under the business combination guidance, including the impact of income taxes, is preliminary. The preliminary fair value allocation is subject to change for up to one year subsequent to the Acquisition Date. Determining the fair value of the assets and liabilities of Allkem requires judgement and certain assumptions to be made, the most significant of these being related to the valuation of Allkem's mining properties and rights. Transaction and related costs directly attributable to the acquisition of Allkem, consisting primarily of advisor fees, legal fees, accounting fees, and certain deal related bonuses were $67 million, for the three months ended March 31, 2024. The costs were expensed as incurred and are included in restructuring and other charges. The following table summarizes the preliminary purchase price allocation for the Allkem Livent Merger as of January 4, 2024, which is subject to change: (in Millions, except per share amounts) Amount Total consideration $ 4,390.4  Assets acquired: Cash and cash equivalents $ 681.4  Trade receivables 64.2  Inventories 121.3  Prepaid and other current assets 87.2  Property, plant and equipment 4,325.5  Right of use assets - operating leases, net 53.4  Deferred income tax assets 26.3  Other assets (1) 192.9  Total assets acquired $ 5,552.2  Liabilities assumed: Accounts payable, trade and other $ 221.9  Accrued and other current liabilities 35.1  Income taxes 78.8  Long-term debt including current portion 301.7  Operating lease liabilities - long-term 53.4  Environmental liabilities 18.9  Deferred income tax liabilities 1,316.7  Other long-term liabilities 49.5  Total liabilities assumed $ 2,076.0  Fair value of net assets acquired $ 3,476.2  Add: Fair value of noncontrolling interests acquired 275.0  Fair value of net assets acquired less noncontrolling interests acquired $ 3,201.2  Goodwill $ 1,189.2  ___________________ 1.Includes long-term semi-finished goods inventory. Trade receivables The $64.2 million of acquired trade receivables represents the fair value of the gross amount due under the contracts. Property, Plant and Equipment Property, plant and equipment is inclusive of the fair value of mineral rights totaling $2,745 million and non-mineral rights property, plant and equipment totaling $1,580.5 million. The fair value of the mineral rights was estimated using the multi-period excess earnings method. The excess earnings methodology is an income approach methodology that estimates the projected cash flows of the business attributable to the asset, net of charges for the use of other identifiable assets of the business including working capital, fixed assets, and other intangible assets. Mineral rights are depreciated using a units-of-production method while all other property, plant and equipment is depreciated using the straight-line method. Goodwill Goodwill from acquisitions represents the excess of the purchase price over the fair value of net assets acquired. The amount disclosed within the table, subject to change for up to on year subsequent to the Acquisition Date, is attributable to the value of growth opportunities and expected synergies created by incorporating Allkem's business and operations into the Company's operations and the value of the assembled workforce. The goodwill has no amortizable basis for income tax purposes. Allkem revenues and earnings The following table represents Allkem's revenues and net earnings included in Arcadium's condensed consolidated statements of operations from the Acquisition Date through March 31, 2024. (in Millions) Three Months Ended March 31, 2024 Revenue $ 102.5  Income from operations before income taxes $ 78.2  Pro Forma Financial Information Due to the Allkem Livent Merger closing on January 4, 2024, all activity in the first quarter of 2024 except for the first three days of January, which management deemed not material, is included in Arcadium’s condensed consolidated statements of operations. The following unaudited pro forma financial information for the three months ended March 31, 2023 is based on our historical consolidated financial statements adjusted to reflect the Allkem Livent Merger as if it occurred on January 1, 2023, the first day of the most recently completed fiscal year. The unaudited pro forma financial information is not necessarily indicative of what would have occurred if the Allkem Livent Merger had been completed as of the beginning of the periods presented, nor is it indicative of future results. The unaudited pro forma information is not necessarily indicative of operating results that would have been achieved had the acquisition been completed as of January 1, 2023 and does not intend to project the future financial results of the Company after the acquisition. The unaudited pro forma information is based on certain assumptions, which management believes are reasonable, and does not reflect the cost of any integration activities or synergies that may be derived from any integration activities. The unaudited pro forma financial results are as follows: (in Millions) Three Months Ended March 31, 2023 (Unaudited) Revenue $ 569.4  Net income $ 234.1

v3.24.1.1.u2

Goodwill	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The following table summarizes the changes in goodwill for the three months ended March 31, 2024. (in Millions) Allkem Nemaska Lithium Total Balance as of December 31, 2023 $ —  $ 120.7  $ 120.7  Acquisitions - Allkem Livent Merger 1,189.2  —  1,189.2  Balance as of March 31, 2024 $ 1,189.2  $ 120.7  $ 1,309.9  See Note 4 for further details.

v3.24.1.1.u2

Revenue Recognition	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue Recognition	Revenue Recognition      Disaggregation of revenue We disaggregate revenue from contracts with customers by geographical areas (based on product destination) and by product categories. The following table provides information about disaggregated revenue by major geographical region: (in Millions) Three Months Ended March 31, 2024 2023 Asia Pacific (1) $ 220.1  $ 167.0  North America (1) 20.7  51.9  Europe, Middle East & Africa 19.6  32.8  Latin America 0.8  1.8  Consolidated Revenue $ 261.2  $ 253.5  1.During the three months ended March 31, 2024, countries with sales in excess of 10% of consolidated revenue consisted of China, Japan, and South Korea. Sales for the three months ended March 31, 2024 for China, Japan, and South Korea totaled $125.9 million, $46.0 million, and $45.5 million, respectively. During the three months ended March 31, 2023, countries with sales in excess of 10% of consolidated revenue consisted of China, the U.S., South Korea, and Japan. Sales for the three months ended March 31, 2023 for China, the U.S., South Korea, and Japan totaled $88.4 million, $50.2 million, and $35.1 million, and $33.4 million, respectively. For the three months ended March 31, 2024, three customers accounted for approximately 22%, 16%, and 14%, respectively, of consolidated revenue and our 10 largest customers accounted in aggregate for approximately 79% of consolidated revenue. For the three months ended March 31, 2023, two customers accounted for approximately 25% and 19% of consolidated revenue and our 10 largest customers accounted in aggregate for approximately 68% of consolidated revenue. A loss of any material customer could have a material adverse effect on our business, financial condition and results of operations. The following table provides information about disaggregated revenue by major product category: (in Millions) Three Months Ended March 31, 2024 2023 Lithium Hydroxide $ 110.6  $ 152.7  Lithium Carbonate (1) 79.8  9.5  Butyllithium and Other Lithium Specialties 46.0  91.3  Spodumene Concentrate (2) 24.8  —  Consolidated Revenue $ 261.2  $ 253.5  ______________________ 1.Includes lithium carbonate by-product revenue. 2.Includes low-grade spodumene sales and minimal other products. Contract asset and contract liability balances We satisfy our obligations by transferring goods and services in exchange for consideration from customers. The timing of performance sometimes differs from the timing the associated consideration is received from the customer, thus resulting in the recognition of a contract asset or liability. Provisional pricing within certain of our customer contracts may result in recognition of a contract asset or liability. We recognize a contract liability if the customer’s payment of consideration is received prior to completion of our related performance obligation. The following table presents the opening and closing balances of our contract liabilities and current trade receivables, net of allowances from contracts with customers. (in Millions) Balance as of March 31, 2024 Balance as of December 31, 2023 (Decrease)/increase Receivables from contracts with customers, net of allowances $ 93.5  $ 106.7  $ (13.2) Contract liability - short-term 30.6  4.4  26.2  Contract liability - long-term 218.3  217.8  0.5  Performance obligations Occasionally, we may enter into multi-year take or pay supply agreements with customers. The aggregate amount of revenue expected to be recognized related to these contracts’ performance obligations is approximately $1.8 billion in the next five years. Based on our past experience with the customers under these arrangements, we expect to continue recognizing revenue in accordance with the contracts as we transfer control of the product to the customer. However, in the case a shortfall of volume purchases occurs, we will recognize the amount payable by the customer over the remaining performance obligations in the contract.

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Inventories, Net	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventories, Net	Inventories, Net Inventories consisted of the following:  (in Millions) March 31, 2024 December 31, 2023 Finished goods $ 114.1  $ 59.1  Semi-finished goods 122.2  108.8  Raw materials, supplies, and other 92.5  49.6  Inventory, net $ 328.8  $ 217.5  Inventories are stated at the lower of cost or net realizable value. Inventory costs include those costs directly attributable to products before sale, including all manufacturing overhead but excluding distribution costs. All inventories are determined on a first-in, first-out ("FIFO") basis.

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Investments	3 Months Ended
	Mar. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]
Investments	Investments     Investments consisted of the following:  (in Millions) March 31, 2024 December 31, 2023 ESM ILiAD, LLC $ 30.1  $ 30.1  Arcadium NQSP 6.0  4.7  Other 2.5  —  Investments $ 38.6  $ 34.8  ESM ILiAD, LLC ("ESM") In the fourth quarter of 2023, the Company entered into an agreement with EnergySource Minerals, LLC ("EnergySource"), a developer of lithium projects in the Salton Sea Known Geothermal Resource Area in California, for a minority equity interest in ESM, a subsidiary of EnergySource and the parent company of ILiAD Technologies, LLC ("ILiAD Technologies"). In connection with its investment in ESM, Arcadium Lithium will have the right to license ILiAD Technologies' Integrated Lithium Adsorption Desorption ("ILiAD") technology for potential deployment at its lithium brine resources in Argentina. Arcadium Lithium accounts for its interest in ESM under ASC Topic 321, Investments – Equity Securities ("ASC 321"). Since our investment in ESM does not have a readily determinable fair value, we use the measurement alternative under ASC 321. Our investment is measured at cost less impairments, adjusted for observable price changes in orderly transactions for the identical or similar investment of the same issuer. If the Company determines that an indicator of impairment or upward adjustment is present, an adjustment is recorded, which is measured as the difference between carrying value and estimated fair value. Estimated fair value is generally determined using an income approach on discounted cash flows or negotiated transaction values. As of March 31, 2024 and December 31, 2023, the carrying amount of our investment in ESM was $30.1 million. Toyotsu Lithium Corporation ("TLC") The Company owns 49% of the Class A voting shares and 100% of the Class B non-voting shares in TLC. Toyota Tsusho Corporation ("TTC") owns 51% of the Class A voting shares. As a result, the Company has a 75% economic interest and a 49% ownership interest in TLC and TTC has the remaining 25% economic interest and 51% ownership interest in TLC. TLC constructed and now operates the Naraha Lithium Hydroxide Plant (the "Naraha Plant"), located in Japan. The technical grade lithium carbonate feedstock for the plant is sourced from the Company’s Olaroz Plant. The Company accounts for its interest in TLC as an equity method investment because it does not have control but has significant influence. This is evidenced by the Company having 2 of the 5 board members while decisions are made by a majority. In addition to capital contributions made through its investment in TLC, Allkem has also provided past funding through loans. At the Acquisition Date, the carrying values of the investment in TLC and a fully reserved loan receivable were zero and fair value was deemed to be equal to carrying value. For the three months ended March 31, 2024, we did not record any gains or losses related to our interest in TLC to Equity in net loss of unconsolidated affiliates in our condensed consolidated statements of operations. At March 31, 2024, the carrying values of our interest in TLC and the loan receivable were zero. Partially-Owned Subsidiaries and Noncontrolling Interests Nemaska Lithium Inc. ("Nemaska Lithium", or "NLI") Nemaska Lithium, domiciled in Canada and headquartered in Montreal, Québec, is a non-public lithium company not yet in the production stage. It is a development company aiming to vertically integrate, from extracting, processing and concentrating spodumene to conversion of spodumene into battery-grade lithium hydroxide, primarily intended for EV and other energy storage applications. Its primary assets are construction in progress and intangibles principally related to intellectual property. Nemaska Lithium intends to develop the Whabouchi spodumene mine and concentrator in the James Bay region of Québec and a lithium hydroxide conversion plant in Bécancour, Québec (collectively, the "Nemaska Lithium Project"). As a developing company and to fund the Nemaska Lithium Project, Nemaska Lithium is reliant on securing financing from its shareholders through share subscriptions. On October 18, 2023, we entered into an amendment to our shareholders agreement with Nemaska Lithium, and also amendments to certain related service agreements. The amendments to these agreements provide QLP with control of certain substantive participating rights, and as such, the Company began to consolidate Nemaska Lithium as of October 18, 2023. Nemaska Lithium is a development company which, as of the October 18, 2023 consolidation date, met the U.S. GAAP definition of a business and, as such, the Company remeasured its equity interest in Nemaska, including the noncontrolling interest of Investissement Québec ("IQ"), at fair value as of the consolidation date. We estimated the fair value of IQ's noncontrolling interest by multiplying the total fair value of Nemaska Lithium equity by IQ's equity ownership interest and also considered any discounts for lack of control and marketability. The fair value of the assets and liabilities of Nemaska Lithium assumed under business combination accounting guidance for the Nemaska Lithium consolidation, including the impact of income taxes, is preliminary. The preliminary fair value allocation is subject to change for up to one year subsequent to the October 18, 2023 consolidation date of Nemaska Lithium. Determining the fair value of the assets and liabilities of Nemaska Lithium requires judgment and certain assumptions to be made, the most significant of these being related to the valuation of Nemaska Lithium's mining properties and rights. Nemaska Lithium is consolidated on a one-quarter lag basis. Before October 18, 2023, the Company accounted for its 50% interest in Nemaska Lithium as an equity method investment on a one-quarter lag basis and it was included in Investments in our consolidated balance sheets. The carrying amount of our interest in Nemaska Lithium was $437.1 million as of December 31, 2022 under equity method investment accounting. For the three months ended March 31, 2023 we recorded a $8.1 million loss related to our interest in Nemaska Lithium to Equity in net loss of unconsolidated affiliate in our condensed consolidated statements of operations. Arcadium's cash and cash equivalents balance in its condensed consolidated balance sheet as of March 31, 2024 includes Nemaska Lithium's cash of $43 million at December 31, 2023 as Nemaska Lithium is consolidated on a one-quarter lag. All cash at Nemaska Lithium will be used for capital expenditures and operating expenses of the Nemaska Lithium Project. On March 28, 2024, Nemaska Lithium received cash of $150 million related to a second advance payment in connection with a customer supply agreement repayable in equal quarterly installments beginning in January 2027 and ending in October 2031. The related liability will be $97.8 million debt and $52.2 million contract liability. A total of $350 million in prepayments are expected from the customer and as of March 31, 2024, $225 million has been received. Sales de Jujuy Pte Ltd and Sales de Jujuy S.A. The Company has an interest of 72.68% in Sales de Jujuy Pte Ltd ("SDJ Pte"), 66.5% in Sales de Jujuy S.A. ("SDJ SA"), the legal entities which operate the Olaroz Lithium Facility (the "Olaroz Plant"). Located in the Jujuy Province of northern Argentina, the Olaroz Plant produces lithium carbonate chemicals for the battery, technical and chemical markets. The Olaroz Plant is operated through SDJ SA, which is a 91.5% owned subsidiary of SDJ Pte, a Singaporean company owned by Arcadium (72.68%) and Toyotsu Lithium Pte Ltd. (27.32%), an affiliated company of TTC. Jujuy Energia y Minera Sociedad del Estado ("JEMSE") owns the remaining 8.5% of SDJ SA. Consequently, the effective equity ownership of the Olaroz Plant is 66.5% by Arcadium, 25% by TTC, and 8.5% by JEMSE. As of March 31, 2024, Arcadium had cash set aside of $24.6 million in other noncurrent assets in its condensed consolidated balance sheets for the guarantee of SDJ SA's Olaroz Project Loan Facility for Stage 1 and Stage 2. See Note 14 for details. Arcadium's cash and cash equivalents balance in its condensed consolidated balance sheet as of March 31, 2024 includes $89.5 million held by the entities discussed above. Arcadium funded JEMSE’s equity contributions in SDJ SA with an interest-free loan (the "JEMSE Receivable") to be repaid by JEMSE out of 33% of the dividends it receives from SDJ SA. The fair value of the non-current receivable is $5.5 million as of March 31, 2024.

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Partially-Owned Subsidiaries and Noncontrolling Interests	3 Months Ended
	Mar. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]
Partially-Owned Subsidiaries and Noncontrolling Interests	Investments     Investments consisted of the following:  (in Millions) March 31, 2024 December 31, 2023 ESM ILiAD, LLC $ 30.1  $ 30.1  Arcadium NQSP 6.0  4.7  Other 2.5  —  Investments $ 38.6  $ 34.8  ESM ILiAD, LLC ("ESM") In the fourth quarter of 2023, the Company entered into an agreement with EnergySource Minerals, LLC ("EnergySource"), a developer of lithium projects in the Salton Sea Known Geothermal Resource Area in California, for a minority equity interest in ESM, a subsidiary of EnergySource and the parent company of ILiAD Technologies, LLC ("ILiAD Technologies"). In connection with its investment in ESM, Arcadium Lithium will have the right to license ILiAD Technologies' Integrated Lithium Adsorption Desorption ("ILiAD") technology for potential deployment at its lithium brine resources in Argentina. Arcadium Lithium accounts for its interest in ESM under ASC Topic 321, Investments – Equity Securities ("ASC 321"). Since our investment in ESM does not have a readily determinable fair value, we use the measurement alternative under ASC 321. Our investment is measured at cost less impairments, adjusted for observable price changes in orderly transactions for the identical or similar investment of the same issuer. If the Company determines that an indicator of impairment or upward adjustment is present, an adjustment is recorded, which is measured as the difference between carrying value and estimated fair value. Estimated fair value is generally determined using an income approach on discounted cash flows or negotiated transaction values. As of March 31, 2024 and December 31, 2023, the carrying amount of our investment in ESM was $30.1 million. Toyotsu Lithium Corporation ("TLC") The Company owns 49% of the Class A voting shares and 100% of the Class B non-voting shares in TLC. Toyota Tsusho Corporation ("TTC") owns 51% of the Class A voting shares. As a result, the Company has a 75% economic interest and a 49% ownership interest in TLC and TTC has the remaining 25% economic interest and 51% ownership interest in TLC. TLC constructed and now operates the Naraha Lithium Hydroxide Plant (the "Naraha Plant"), located in Japan. The technical grade lithium carbonate feedstock for the plant is sourced from the Company’s Olaroz Plant. The Company accounts for its interest in TLC as an equity method investment because it does not have control but has significant influence. This is evidenced by the Company having 2 of the 5 board members while decisions are made by a majority. In addition to capital contributions made through its investment in TLC, Allkem has also provided past funding through loans. At the Acquisition Date, the carrying values of the investment in TLC and a fully reserved loan receivable were zero and fair value was deemed to be equal to carrying value. For the three months ended March 31, 2024, we did not record any gains or losses related to our interest in TLC to Equity in net loss of unconsolidated affiliates in our condensed consolidated statements of operations. At March 31, 2024, the carrying values of our interest in TLC and the loan receivable were zero. Partially-Owned Subsidiaries and Noncontrolling Interests Nemaska Lithium Inc. ("Nemaska Lithium", or "NLI") Nemaska Lithium, domiciled in Canada and headquartered in Montreal, Québec, is a non-public lithium company not yet in the production stage. It is a development company aiming to vertically integrate, from extracting, processing and concentrating spodumene to conversion of spodumene into battery-grade lithium hydroxide, primarily intended for EV and other energy storage applications. Its primary assets are construction in progress and intangibles principally related to intellectual property. Nemaska Lithium intends to develop the Whabouchi spodumene mine and concentrator in the James Bay region of Québec and a lithium hydroxide conversion plant in Bécancour, Québec (collectively, the "Nemaska Lithium Project"). As a developing company and to fund the Nemaska Lithium Project, Nemaska Lithium is reliant on securing financing from its shareholders through share subscriptions. On October 18, 2023, we entered into an amendment to our shareholders agreement with Nemaska Lithium, and also amendments to certain related service agreements. The amendments to these agreements provide QLP with control of certain substantive participating rights, and as such, the Company began to consolidate Nemaska Lithium as of October 18, 2023. Nemaska Lithium is a development company which, as of the October 18, 2023 consolidation date, met the U.S. GAAP definition of a business and, as such, the Company remeasured its equity interest in Nemaska, including the noncontrolling interest of Investissement Québec ("IQ"), at fair value as of the consolidation date. We estimated the fair value of IQ's noncontrolling interest by multiplying the total fair value of Nemaska Lithium equity by IQ's equity ownership interest and also considered any discounts for lack of control and marketability. The fair value of the assets and liabilities of Nemaska Lithium assumed under business combination accounting guidance for the Nemaska Lithium consolidation, including the impact of income taxes, is preliminary. The preliminary fair value allocation is subject to change for up to one year subsequent to the October 18, 2023 consolidation date of Nemaska Lithium. Determining the fair value of the assets and liabilities of Nemaska Lithium requires judgment and certain assumptions to be made, the most significant of these being related to the valuation of Nemaska Lithium's mining properties and rights. Nemaska Lithium is consolidated on a one-quarter lag basis. Before October 18, 2023, the Company accounted for its 50% interest in Nemaska Lithium as an equity method investment on a one-quarter lag basis and it was included in Investments in our consolidated balance sheets. The carrying amount of our interest in Nemaska Lithium was $437.1 million as of December 31, 2022 under equity method investment accounting. For the three months ended March 31, 2023 we recorded a $8.1 million loss related to our interest in Nemaska Lithium to Equity in net loss of unconsolidated affiliate in our condensed consolidated statements of operations. Arcadium's cash and cash equivalents balance in its condensed consolidated balance sheet as of March 31, 2024 includes Nemaska Lithium's cash of $43 million at December 31, 2023 as Nemaska Lithium is consolidated on a one-quarter lag. All cash at Nemaska Lithium will be used for capital expenditures and operating expenses of the Nemaska Lithium Project. On March 28, 2024, Nemaska Lithium received cash of $150 million related to a second advance payment in connection with a customer supply agreement repayable in equal quarterly installments beginning in January 2027 and ending in October 2031. The related liability will be $97.8 million debt and $52.2 million contract liability. A total of $350 million in prepayments are expected from the customer and as of March 31, 2024, $225 million has been received. Sales de Jujuy Pte Ltd and Sales de Jujuy S.A. The Company has an interest of 72.68% in Sales de Jujuy Pte Ltd ("SDJ Pte"), 66.5% in Sales de Jujuy S.A. ("SDJ SA"), the legal entities which operate the Olaroz Lithium Facility (the "Olaroz Plant"). Located in the Jujuy Province of northern Argentina, the Olaroz Plant produces lithium carbonate chemicals for the battery, technical and chemical markets. The Olaroz Plant is operated through SDJ SA, which is a 91.5% owned subsidiary of SDJ Pte, a Singaporean company owned by Arcadium (72.68%) and Toyotsu Lithium Pte Ltd. (27.32%), an affiliated company of TTC. Jujuy Energia y Minera Sociedad del Estado ("JEMSE") owns the remaining 8.5% of SDJ SA. Consequently, the effective equity ownership of the Olaroz Plant is 66.5% by Arcadium, 25% by TTC, and 8.5% by JEMSE. As of March 31, 2024, Arcadium had cash set aside of $24.6 million in other noncurrent assets in its condensed consolidated balance sheets for the guarantee of SDJ SA's Olaroz Project Loan Facility for Stage 1 and Stage 2. See Note 14 for details. Arcadium's cash and cash equivalents balance in its condensed consolidated balance sheet as of March 31, 2024 includes $89.5 million held by the entities discussed above. Arcadium funded JEMSE’s equity contributions in SDJ SA with an interest-free loan (the "JEMSE Receivable") to be repaid by JEMSE out of 33% of the dividends it receives from SDJ SA. The fair value of the non-current receivable is $5.5 million as of March 31, 2024.

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Property, Plant and Equipment, Net	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment, Net	Property, Plant and Equipment, Net Property, plant and equipment consisted of the following: (in Millions) March 31, 2024 December 31, 2023 Land and land improvements $ 325.2  $ 106.2  Buildings 724.5  134.9  Machinery and equipment 791.6  420.7  Mineral rights 3,278.0  560.0  Construction in progress 1,953.5  1,284.4  Total cost $ 7,072.8  $ 2,506.2  Accumulated depreciation (279.1) (269.1) Property, plant and equipment, net $ 6,793.7  $ 2,237.1  Depreciation is calculated principally on a straight-line basis over the estimated useful lives of the assets or a units-of-production basis based on the rate of depletion of reserves. Land is not depreciated. The major classifications of property, equipment and software, including their respective principal depreciation and amortization method and expected useful lives, consisted of the following: Asset type Depreciation and amortization method Useful Life Land N/A — Land improvements Straight-line 20 years Buildings Straight-line 20-40 years Mineral rights Units-of-production Based on rate of depletion of reserves Mining extraction equipment Units-of-production Based on rate of depletion of reserves Leased plant and equipment Straight-line Lease period (1-10.5 years) Other machinery and equipment Straight-line 3-18 years Software Straight-line 3-10 years Depreciation expense was $15.4 and $6.1 million for the three months ended March 31, 2024 and 2023, respectively.

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Restructuring and Other Charges	3 Months Ended
	Mar. 31, 2024
Restructuring and Related Activities [Abstract]
Restructuring and Other Charges	Restructuring and Other Charges The following table shows other charges included in "Restructuring and other charges" in the condensed consolidated statements of operations: Three Months Ended March 31, (in Millions) 2024 2023 Restructuring charges: Severance-related and exit costs $ 10.9  $ 1.7  Other charges: Costs related to the Allkem Livent Merger 67.0  —  Other 5.7  0.2  Total Restructuring and other charges $ 83.6  $ 1.9

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Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We determine our interim tax provision using an estimated annual effective tax rate methodology ("EAETR") in accordance with U.S. GAAP. The EAETR is applied to the year-to-date ordinary income, exclusive of discrete items. The tax effects of discrete items are then included to arrive at the total reported interim tax provision. The determination of the EAETR is based upon a number of estimates, including the estimated annual pretax ordinary income in each tax jurisdiction in which we operate. As our projections of ordinary income change throughout the year, the EAETR will change period-to-period. The tax effects of discrete items are recognized in the tax provision in the period they occur in accordance with U.S. GAAP. Depending on various factors, such as the item’s significance in relation to total income and the rate of tax applicable in the jurisdiction to which it relates, discrete items in any quarter can materially impact the reported effective tax rate. As a global enterprise, our tax expense can be impacted by changes in tax rates or laws, the finalization of tax audits and reviews, as well as other factors. As a result, there can be significant volatility in interim tax provisions. Provision for income taxes for the three months ended March 31, 2024 was an expense of $53.8 million resulting in an effective tax rate of 73.0%. Provision for income taxes for the three months ended March 31, 2023 was an expense of $23.9 million resulting in an effective tax rate of 17.2%.

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Asset Retirement Obligations	3 Months Ended
	Mar. 31, 2024
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligation	Asset Retirement ObligationsLegacy Allkem asset retirement obligations acquired in the Allkem Livent Merger were recorded at fair value on the Acquisition Date and consist of $7.3 million, $1.5 million and $0.9 million related to the Mt Cattlin spodumene mine in Western Australia, the Olaroz lithium brine extraction facility in Jujuy, Argentina and the Sal de Vida lithium brine extraction facility (currently under development) in Catamarca, Argentina, respectively.

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Debt	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Debt	Debt Long-term debt Long-term debt consists of the following: Interest Rate Percentage Maturity Date March 31, 2024 December 31, 2023 (in Millions) SOFR borrowings Base rate borrowings Revolving Credit Facility (1) 7.18% 9.25% 2027 $ —  $ —  4.125% Convertible Senior Notes due 2025 4.125% 2025 245.8  245.8  Transaction costs - 2025 Notes (2.0) (2.4) Nemaska - Prepayment agreement (2) 8.9% 75.0  75.0  Discount - Prepayment agreement (20.2) (19.8) Nemaska - Other 0.4  3.4  Debt assumed in Allkem Livent Merger Project Loan Facility - Stage 1 of Olaroz Plant 4.896% 2024 9.2  —  Project Loan Facility - Stage 2 of Olaroz Plant 2.612% 2029 144.0  —  Project Financing Facility - Sal de Vida 10.051% 2030 47.0  —  Affiliate Loans with TTC 11.331% 2030 81.6  —  Affiliate Loan with TLP 10.34% 2026 2.5  —  Total debt assumed in Allkem Livent Merger 284.3  —  Subtotal long-term debt (including current maturities) 583.3  302.0  Less current maturities $ (80.6) $ (2.4) Total long-term debt $ 502.7  $ 299.6  ______________________________ 1.As of March 31, 2024 and December 31, 2023, there were $15.5 million in letters of credit outstanding under our Revolving Credit Facility and $484.5 million available funds. Fund availability is subject to the Company meeting its debt covenants. 2.Represents first advance payment in connection with customer supply agreement repayable in equal quarterly installments beginning in January 2027 and ending in October 2031. Represents U.S. GAAP imputed interest rate. On March 28, 2024, Nemaska Lithium received a second advance payment of $150 million in connection with the customer supply agreement, with a discount of $52.2 million. 4.125% Convertible Senior Notes due 2025 In 2020, the Company issued $245.8 million in aggregate principal amount of 4.125% Convertible Senior Notes due in July 2025 (the "2025 Notes"). The 2025 Notes are our general unsecured senior obligations. Total net cash proceeds received were $238.2 million net of $7.6 million of third-party transaction costs, including initial purchasers' discounts and commissions. The Company used or will use the net proceeds received to finance or refinance eligible green projects designed to align with the provisions of the International Capital Market Association Green Bond Principles 2018. Each $1,000 of principal of the 2025 Notes was initially convertible into 114.4885 shares of common stock of Livent Corporation, which was equivalent to an initial conversion price of $8.73 per share, subject to adjustment upon the occurrence of specified events. Following the effectiveness of that certain First Supplemental Indenture, dated as of January 4, 2024, by and among the Company, Livent Corporation and U.S. Bank Trust Company, National Association, each $1,000 of principal of the 2025 Notes is convertible into 275.459331 shares of our ordinary shares, which is equivalent to a conversion price of $3.63 per share, subject to adjustment upon the occurrence of specified events. We may redeem for cash all or any portion of the 2025 Notes, at our option, if the last reported sale price of our ordinary shares has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which we provide notice of redemption at a redemption price equal to 100% of the principal amount of the 2025 Notes to be redeemed, plus accrued and unpaid interest. Holders of the 2025 Notes may convert their notes at any time, at their option, on or after January 15, 2025. Further, holders of the 2025 Notes may convert their notes at any time, at their option, prior to January 15, 2025 only under the following circumstances: (1) during any calendar quarter commencing after September 30, 2020 (and only during such calendar quarter), if the last reported sale price of our ordinary shares for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each trading day; (2) during the five-business day period after any five-consecutive trading day period in which the trading price per $1,000 principal amount of the 2025 Notes for each trading day of such period is less than 98% of the product of the last reported sale price of our ordinary shares and the conversion rate on each such trading day, (3) if we call any or all of the 2020 Notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date or (4) if specified corporate events occur. Upon conversion, the 2025 Notes will be settled in cash, shares of our ordinary shares or a combination thereof, at our election. If a fundamental change occurs prior to the maturity date, holders of the 2025 Notes may require us to repurchase all or a portion of their 2025 Notes for cash at a repurchase price equal to 100% of the principal amount plus any accrued and unpaid interest. In addition, if specific corporate events occur prior to the maturity date or if we deliver a notice of redemption, we will increase the conversion rate for a holder who elects to convert its 2025 Notes in connection with such an event or notice of redemption in certain circumstances. The last reported sale price of our ordinary shares for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on, and including, March 31, 2024 was not greater than or equal to 130% of the conversion price as adjusted for the Allkem Livent Merger, which is $4.72, on each trading day, and as a result, the holders do not have the option to convert all or any portion of their 2025 Notes through June 30, 2024. The conversion rate for the 2025 Notes is 275.4593 ordinary shares of Arcadium Lithium per $1,000 principal amount of 2025 Notes. The 2025 Notes mature in July 2025 and are classified as long-term debt. The Company recognized non-cash interest related to the amortization of transaction costs for the 2025 Notes of $0.4 million for the three months ended March 31, 2024, all of which was capitalized. The Company recorded $2.5 million of accrued interest expense related to the principal amount for the three months ended March 31, 2024, all of which was capitalized. Amended and Restated Credit Agreement, (the "Revolving Credit Facility") On January 4, 2024, Livent Corporation, Livent USA Corp., the Company, Arcadium Lithium Financing IRL Limited ("FinCo") and Irish IntermediateCo (collectively, the "Borrowers" and, each, a "Borrower"), the guarantors party thereto from time to time (the "Guarantors"), the lenders party thereto (the "Lenders") and issuing banks party thereto and Citibank, N.A., as administrative agent (the "Administrative Agent") for the Lenders, entered into a Joinder and First Amendment (the "Credit Agreement Amendment") to that certain Amended and Restated Credit Agreement, dated as of September 1, 2022, among Livent, Livent USA Corp., the guarantors party thereto from time to time, the lenders party thereto from time to time and the Administrative Agent (the "Credit Agreement" and as amended by the Credit Agreement Amendment, the Amended Credit Agreement"). The Credit Agreement Amendment provided for, among other things, (i) the addition of Arcadium, Irish IntermediateCo and FinCo as borrowers and obligors under the Amended Credit Agreement and (ii) the assignment of certain of Livent Corporation's rights and obligations (including information reporting obligations) under the Amended Credit Agreement to Arcadium. The Revolving Credit Facility provides for a $500 million senior secured revolving credit facility, $50 million of which is available for the issuance of letters of credit for the account of the Borrowers, with an option to request, and subject to each Lender’s sole discretion, that the aggregate revolving credit commitments be increased to up to $700 million. The issuance of letters of credit and the proceeds of revolving credit loans made pursuant to the Revolving Credit Facility may be used for general corporate purposes, including capital expenditures and permitted acquisitions. Revolving loans under the Revolving Credit Facility will bear interest at a floating rate, which will be (i) a base rate, (ii) Adjusted Term Secured Overnight Financing Rate ("SOFR") (defined as the forward-looking SOFR term rate published by CME Group Benchmark Administration Limited plus 0.10% per annum subject to a floor of zero) or (iii) Euro Interbank Offered Rate ("EURIBOR"), plus, in each case, an applicable margin, as determined in accordance with the provisions of the Revolving Credit Facility. The Revolving Credit Facility includes a quarterly commitment fee on the average daily unused amount of each Lender’s revolving credit commitment at a rate equal to an applicable percentage based on the Company’s first lien leverage ratio. The initial commitment fee is 0.25% per annum. Amounts under the Revolving Credit Facility may be borrowed, repaid and re-borrowed from time to time until the final maturity date on September 1, 2027. Voluntary prepayments and commitment reductions are permitted at any time without payment of any prepayment fee upon proper notice and subject to minimum dollar amounts. Certain of the Borrowers’ domestic subsidiaries (the "Guarantors") guarantee the obligations of the Borrowers under the Revolving Credit Facility. The obligations of the Borrower and the Guarantors are secured by all of the assets of the Borrowers and the Guarantors, including the Borrowers’ facility and real estate in Bessemer City, North Carolina, subject to certain exceptions and exclusions. We recorded $0.8 million of incremental deferred financing costs in the condensed consolidated balance sheets for the Revolving Credit Facility commitment and legal fees and a $0.2 million loss on debt extinguishment in the condensed consolidated statements of operations for the three months ended March 31, 2024 for the write off of existing deferred financing costs to recognize a partial change in syndication related to the Revolving Credit Facility. The carrying value of our deferred financing costs was $2.7 million as of March 31, 2024 and is recorded to Other assets in our condensed consolidated balance sheet. Covenants The Credit Agreement contains certain affirmative and negative covenants that are binding on us and our subsidiary, Livent USA Corp., as borrowers (the "Borrowers") and their subsidiaries, including, among others, restrictions (subject to exceptions and qualifications) on the ability of the Borrowers and their subsidiaries to create liens, to undertake fundamental changes, to incur debt, to sell or dispose of assets, to make investments, to make restricted payments such as dividends, distributions or equity repurchases, to change the nature of their businesses, to enter into transactions with affiliates and to enter into certain restrictive agreements. Furthermore, the Borrowers are subject to financial covenants regarding leverage (measured as the ratio of debt to adjusted earnings) and interest coverage (measured as the ratio of adjusted earnings to interest expense). Our maximum allowable first lien leverage ratio is 3.5 as of March 31, 2024. Our minimum allowable interest coverage ratio is 3.5. We were in compliance with all requirements of the covenants as of March 31, 2024. Debt assumed as a result of Allkem Livent Merger The following is a summary of Allkem's indebtedness that Arcadium Lithium assumed as a result of the Allkem Livent Merger. Project Loan Facility SDJ SA has a project loan facility with Mizuho Bank related to the Olaroz Plant (the "Project Loan Facility"): •The Project Loan Facility for Stage 1 of the Olaroz Plant had an outstanding principal balance of $9.2 million as of March 31, 2024. The interest rate for the Stage 1 loan is the SOFR plus a margin of 0.80%. The interest rate related to 88.6% of the loan was hedged in 2015 with such rate currently at 4.896% until the last repayment in September 2024. Sales de Jujuy Pte Ltd has provided security in favor of Mizuho Bank over the shares it owns in SDJ SA and the Japan Organization for Metals and Energy Security, which covers 82.35% of the outstanding principal amount; and •The Project Loan Facility for Stage 2 of the Olaroz project had an outstanding balance of $144.0 million as of March 31, 2024. The interest rate for the Stage 2 loan is a fixed rate of 2.6119% per annum until expiry in March 2029. As of March 31, 2024, Arcadium had cash set aside of $24.6 million in other noncurrent assets in its condensed consolidated balance sheets for the guarantee of the Project Loan Facility. Under an arrangement with TTC, Arcadium has reserved $77.8 million as a cash guarantee for the Olaroz Plant Project Loan Facility. Project Financing Facility Galaxy Lithium (SAL DE VIDA) S.A. ("SDV SA"), which is owned 100% by Arcadium, entered into a project financing facility with the International Finance Corporation related to the Sal de Vida development project ("Sal de Vida") in Argentina (the "Project Financing Facility"). The Project Financing Facility originally provided for a total of $180.0 million in limited recourse, sustainability-linked green project financing maturing in March 2033, with repayment commencing in March 2026. The Project Financing Facility had an outstanding principal balance of $47.0 million as of March 31, 2024. Arcadium Lithium expects to pay off the balance of the Project Financing Facility in the second quarter of 2024. The interest rate for the Project Financing Facility is term SOFR plus a margin of 4.8% with adjustments of up to +/- 0.25% based on the performance against agreed sustainability targets, as measured at June 2026, 2028 and 2030. The Project Financing Facility is supported by an Arcadium Lithium parent guarantee until completion of construction and subject to affirmative and negative covenants. As of March 31, 2024, Arcadium had cash set aside of $32.5 million in other noncurrent assets in its condensed consolidated balance sheets for the guarantee of the Project Financing Facility. Affiliate Loans With TTC SDJ SA has eleven loans with TTC related to the Olaroz Plant originally providing for a total of $93.0 million in principal. As of March 31, 2024, the loans have an outstanding principal balance of $81.6 million and are payable ranging from July 2024 until March 2030.

v3.24.1.1.u2

Share-based Compensation	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Share-based Compensation	Share-based Compensation Arcadium Lithium plc Omnibus Incentive Plan (the "Arcadium Plan") As of March 31, 2024, there were 64,548,000 Arcadium ordinary shares authorized for issuance under the Arcadium Plan. The Arcadium Plan provides for the grant of a variety of cash and equity awards to officers, directors, employees and consultants, including share options, restricted shares, restricted share units (including performance units), share appreciation rights, and management incentive awards. The Compensation Committee of the Arcadium Board of Directors (the "Arcadium Committee") has the authority to amend the Arcadium Plan at any time, approve financial targets, award grants, establish performance objectives and conditions and the times and conditions for payment of awards. Share options granted under the Arcadium Plan may be incentive or non-qualified share options. The exercise price for share options may not be less than the fair market value of the share at the date of grant. Awards granted under the Arcadium Plan vest or become exercisable or payable at the time designated by the Arcadium Committee. The options granted in 2024 will vest on the first, second and third anniversaries of the date of grant, subject generally to continued employment, and cost is recognized over the vesting period. Incentive and non-qualified options granted under the Arcadium Plan expire not later than 10 years from the grant date. Under the Arcadium Plan, awards of restricted share units ("RSUs") vest over periods designated by the Arcadium Committee. The RSUs granted in 2024 to employees will vest equally on the first, second and third anniversaries of the grant date, subject generally to continued employment, and cost is recognized over the vesting period. The RSUs granted to non-employee directors in 2024 vest at the Company's next annual meeting of shareholders following the grant date. Compensation cost is recognized over the vesting periods based on the market value of Arcadium ordinary shares on the grant date of the award. Allkem Replacement Awards Pursuant to the Transaction Agreement, the equity awards of Allkem (including performance rights) outstanding as of immediately prior to the closing of the Allkem Livent Merger were converted into equity awards denominated in shares of Arcadium ordinary shares. The Company issued time-based vesting restricted shares in connection with the conversion of such awards. The estimated fair value of the portion of the Allkem equity awards for which the required service period had been completed at the time of the closing of the Allkem Livent Merger was treated as purchase consideration. The remaining estimated fair value is recorded as compensation expense over the remainder of the service period associated with the awards. The Allkem Replacement Awards are authorized for issuance under the Arcadium Plan. Legacy Livent Awards As of March 31, 2024, there were 6,579,305 Arcadium ordinary shares authorized for issuance upon the exercise or settlement of the Legacy Livent Awards. Share Compensation We recognized the following share compensation expense for Legacy Livent Awards and awards under the Arcadium Plan: Three Months Ended March 31, (in Millions) 2024 Share Option Expense, net of taxes of $0.1 $ 0.4  Restricted Share Expense, net of taxes of $0.7 12.4  Performance-Based Restricted Share Expense, net of taxes of less than $0.1 0.4  Total Share Compensation Expense, net of taxes of $0.8 (1) $ 13.2  ____________________  (1)    Gross share compensation charges of $2.3 million and $13.5 million were recorded to "Selling, general and administrative expenses" and "Restructuring and other charges", respectively, in our condensed consolidated statements of operations for the three months ended March 31, 2024. Share Options The grant date fair values of the share options granted in the three months ended March 31, 2024, were estimated using the Black-Scholes option valuation model, the key assumptions for which are listed in the table below. The expected volatility assumption is based on the historical volatility of a group of ten of our publicly traded peers that operate in the specialty chemical sector. The expected life represents the period of time that options granted are expected to be outstanding. The risk-free interest rate is based on U.S. Treasury securities with terms equal to the expected timing of share option exercises as of the grant date. The dividend yield assumption reflects anticipated dividends on Arcadium's ordinary shares. Arcadium share options granted in the three months ended March 31, 2024 will vest equally on the first, second and third anniversaries of the grant date and expire ten years from the date of grant. Black Scholes valuation assumptions for Arcadium Plan share option grants:  Three Months Ended March 31, 2024 Expected dividend yield —% Expected volatility 31.18% Expected life (in years) 6.0 Risk-free interest rate 4.08% The weighted-average grant date fair value of share options granted during the three months ended March 31, 2024 was $1.91 per share. The following summary shows share option activity for the Allkem Livent Merger and the Arcadium Plan for the three months ended March 31, 2024: Number of Options Granted But Not Exercised Weighted-Average Remaining Contractual Life (in Years) Weighted-Average Exercise Price Per Share Aggregate Intrinsic Value (in Millions) Outstanding December 31, 2023 5,060,687  5.6 years $ 6.73  $ 6.5  Granted 2,517,175  $ 4.95  Exercised (53,056) $ 4.05  $ —  Outstanding March 31, 2024 7,524,806  6.6 $ 6.28  $ 0.8  Exercisable at March 31, 2024 4,142,996  4.9 $ 6.25  $ 0.8  As of March 31, 2024, we had total remaining unrecognized compensation cost related to unvested share options of $5.5 million which will be amortized over the weighted-average remaining requisite service period of approximately 1.6 years. Restricted Share Unit Awards The grant date fair value of RSUs under the Arcadium Plan is based on the market price per share of Arcadium's ordinary shares on the date of grant, and the related compensation cost is amortized to expense on a straight-line basis over the vesting period during which the employees perform related services, which for the RSUs granted during the three months ended March 31, 2024, will vest equally on the first, second and third anniversaries of the grant date. Pursuant to the Transaction Agreement, on the Acquisition Date, 927,510 employee RSUs vested on an accelerated pro rata basis. The following table shows RSU activity for the Allkem Livent Merger and the Arcadium Plan for the three months ended March 31, 2024: Restricted Share Units Number of awards Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value (in Millions) Nonvested December 31, 2023 2,287,088  $ 7.83  $ 17.1  Granted (1) 2,238,079  $ 5.99  Vested (2) (1,816,439) $ 7.11  Nonvested March 31, 2024 2,708,728  $ 6.83  $ 10.5  ___________________ 1.The Company granted 1,080,825 Allkem Replacement Awards on January 12, 2024 pursuant to the Transaction Agreement. 2.Immediately prior to the Acquisition Date, 768,440 non-employee Director RSUs vested and were paid out in cash of $5.3 million pursuant to the Transaction Agreement. As of March 31, 2024, the Arcadium Plan had total remaining unrecognized compensation cost related to unvested RSUs of $13.3 million which will be amortized over the weighted-average remaining requisite service period of approximately 1.7 years. Performance-Based Restricted Share Unit ("PRSU") Awards Pursuant to the Transaction Agreement, on the Acquisition Date, 96,885 employee PRSUs vested on an accelerated basis at the higher of the PRSU payout on the accelerated vest date, which was —%, or 100%. The following table shows PRSU activity for the three months ended March 31, 2024. Performance-Based Restricted Share Units Number of awards Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value (in Millions) Nonvested as of December 31, 2023 96,885  $ 9.43  $ 0.7  Vested (96,885) $ 9.43  Nonvested as of March 31, 2024 —  $ —  $ —

v3.24.1.1.u2

Equity	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Equity	Equity After the closing of the Allkem Livent Merger on January 4, 2024 and as of March 31, 2024, we had 5 billion ordinary shares of $1.00 par value each and 125 million preferred shares of $1.00 par value each authorized. The following is a summary of Arcadium's ordinary shares issued and outstanding: Issued Treasury Outstanding Balance as of December 31, 2023 (1) 433,059,946  (263,669) 432,796,277  Issued to Allkem shareholders - Allkem Livent Merger 641,337,840  —  641,337,840  PRSU and RSU awards accelerated - Allkem Livent Merger 648,969  —  648,969  Arcadium RSU awards 15,248  —  15,248  Arcadium share option awards 8,497  —  8,497  Net sales of treasury shares - Arcadium NQSP —  461  461  Balance as of March 31, 2024 1,075,070,500  (263,208) 1,074,807,292  _____________________ 1.Balances outstanding as of December 31, 2023, representing predecessor Livent, have been adjusted to reflect the 2.406 Exchange Ratio. Accumulated other comprehensive loss Summarized below is the roll forward of accumulated other comprehensive loss, net of tax. (in Millions) Foreign currency adjustments Derivative Instruments Total Accumulated other comprehensive loss, net of tax as of December 31, 2023 $ (49.8) $ —  $ (49.8) Other comprehensive (losses)/income before reclassifications (20.2) 0.2  (20.0) Accumulated other comprehensive loss, net of tax as of March 31, 2024 $ (70.0) $ 0.2  $ (69.8) (in Millions) Foreign currency adjustments Derivative Instruments Total Accumulated other comprehensive loss, net of tax as of December 31, 2022 $ (51.0) $ —  $ (51.0) Other comprehensive income before reclassifications 1.5  0.2  1.7  Accumulated other comprehensive loss, net of tax as of March 31, 2023 $ (49.5) $ 0.2  $ (49.3) Dividends For the three months ended March 31, 2024 and 2023, we paid no dividends. We do not expect to pay any dividends in the foreseeable future.

v3.24.1.1.u2

Earnings Per Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Earnings per ordinary share ("EPS") is computed by dividing net income by the weighted average number of common shares outstanding during the period on a basic and diluted basis. Our potentially dilutive securities include potential ordinary shares related to our share options, restricted share units and 2025 Notes. See Note 12 to our consolidated financial statements in Part II, Item 8 of our 2023 Annual Report on Form 10-K for more information. Diluted earnings per share ("Diluted EPS") considers the impact of potentially dilutive securities except in periods in which there is a loss because the inclusion of the potential ordinary shares would have an anti-dilutive effect. Diluted EPS excludes the impact of potential ordinary shares related to our share options in periods in which the option exercise price is greater than the average market price of our ordinary shares for the period. We use the if-converted method when calculating the potential dilutive effect, if any, of our 2025 Notes. Earnings applicable to ordinary shares and ordinary shares used in the calculation of basic and diluted earnings per share are as follows: (in Millions, Except Share and Per Share Data) Three Months Ended March 31, 2024 2023 (1) Numerator: Net income attributable to Arcadium Lithium plc $ 15.6  $ 114.8  Denominator: Weighted average ordinary shares outstanding - basic 1,053.4  432.0  Dilutive share equivalents from share-based plans 1.0  3.6  Dilutive share equivalents from 2025 Notes 67.7  67.7  Weighted average ordinary shares outstanding - diluted 1,122.1  503.3  Basic earnings per ordinary share $ 0.01  $ 0.27  Diluted earnings per ordinary share $ 0.01  $ 0.23  _____________________ 1.For the three months ended March 31, 2023, weighted average ordinary shares outstanding - basic and diluted, dilutive share equivalents and basic and diluted earnings per ordinary share amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Anti-dilutive share options For the three months ended March 31, 2024, options to purchase 3,683,694 shares of our ordinary shares, respectively, at an average exercise price of $7.87 per share were anti-dilutive and not included in the computation of diluted earnings per share because the exercise price of the options was greater than the average market price of the ordinary shares for the three months ended March 31, 2024. For the three months ended March 31, 2023, options to purchase 438,154 shares of our ordinary shares, respectively, at an average exercise price of $9.70 per share were anti-dilutive and not included in the computation of diluted earnings per share because the exercise price of the options was greater than the average market price of the ordinary shares for the three months ended March 31, 2023.

v3.24.1.1.u2

Financial Instruments, Risk Management and Fair Value Measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Financial Instruments, Risk Management and Fair Value Measurements	Financial Instruments, Risk Management and Fair Value Measurements      Our financial instruments include cash and cash equivalents, trade receivables, other current assets, investments held in trust fund, trade payables, derivatives and amounts included in accruals meeting the definition of financial instruments. Investments in the Arcadium NQSP deferred compensation plan trust fund are considered Level 1 investments based on readily available quoted prices in active markets for identical assets. The carrying value of cash and cash equivalents, trade receivables, other current assets, and trade payables approximates their fair value due to their short-term nature and are considered Level 1 investments. Our other financial instruments include the following: Financial Instrument Valuation Method Foreign exchange forward contracts Estimated amounts that would be received or paid to terminate the contracts at the reporting date based on current market prices for applicable currencies. The estimated fair value of our foreign exchange forward contracts has been determined using standard pricing models which take into account the present value of expected future cash flows discounted to the balance sheet date. These standard pricing models utilize inputs derived from, or corroborated by, observable market data such as currency and commodity spot and forward rates. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). The inputs used to measure fair value are classified into the following hierarchy: Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 - Unadjusted quoted prices in active markets for similar assets or liabilities, or unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or inputs other than quoted prices that are observable for the asset or liability. Level 3 - Unobservable inputs for the asset or liability. The estimated fair value and the carrying amount of debt were $688.9 million and $583.3 million, respectively, as of March 31, 2024. Our 2025 Notes are classified as Level 2 in the fair value hierarchy. Use of Derivative Financial Instruments to Manage Risk We mitigate certain financial exposures connected to currency risk through a program of risk management that includes the use of derivative financial instruments. We enter into foreign exchange forward contracts to reduce the effects of fluctuating foreign currency exchange rates. We formally document all relationships between hedging instruments and hedged items, as well as the risk management objective and strategy for undertaking various hedge transactions. This process includes relating derivatives that are designated as fair value or cash flow hedges to specific assets and liabilities on the balance sheet or to specific firm commitments or forecasted transactions. We also assess both at the inception of the hedge and on an ongoing basis, whether each derivative is highly effective in offsetting changes in fair values or cash flows of the hedged item. If we determine that a derivative is not highly effective as a hedge, or if a derivative ceases to be a highly effective hedge, we discontinue hedge accounting with respect to that derivative prospectively. Foreign Currency Exchange Risk Management We conduct business in many foreign countries, exposing earnings, cash flows, and our financial position to foreign currency risks. The majority of these risks arise as a result of foreign currency transactions. The primary currencies for which we have exchange rate exposure are the Euro, the British pound, the Chinese yuan, the Argentine peso, the Australian dollar, the Canadian dollar and the Japanese yen. We currently do not hedge foreign currency risks associated with the Argentine peso due to the limited availability and the high cost of suitable derivative instruments. Our policy is to minimize exposure to adverse changes in currency exchange rates. This is accomplished through a controlled program of risk management that could include the use of foreign currency debt and forward foreign exchange contracts. We also use forward foreign exchange contracts to hedge firm and highly anticipated foreign currency cash flows, with an objective of balancing currency risk to provide adequate protection from significant fluctuations in the currency markets. Concentration of Credit Risk Our counterparties to derivative contracts are primarily major financial institutions. We limit the dollar amount of contracts entered into with any one financial institution and monitor counterparties’ credit ratings. We also enter into master netting agreements with each financial institution, where possible, which helps mitigate the credit risk associated with our financial instruments. While we may be exposed to credit losses due to the nonperformance of counterparties, we consider this risk remote. Accounting for Derivative Instruments and Hedging Activities Cash Flow Hedges We recognize all derivatives on the balance sheet at fair value. On the date we enter into the derivative instrument, we generally designate the derivative as a hedge of the variability of cash flows to be received or paid related to a forecasted transaction (cash flow hedge). We record in accumulated other comprehensive loss ("AOCL") changes in the fair value of derivatives that are designated as and meet all the required criteria for, a cash flow hedge. We then reclassify these amounts into earnings as the underlying hedged item affects earnings. In contrast, we immediately record in earnings changes in the fair value of derivatives that are not designated as cash flow hedges. As of March 31, 2024, we had open foreign currency forward contracts in AOCL in a net after-tax gain position of $0.2 million designated as cash flow hedges of underlying forecasted sales and purchases. As of March 31, 2024, we had open forward contracts with various expiration dates to buy, sell or exchange foreign currencies with a U.S. dollar equivalent of approximately $32.3 million. A net after-tax gain of $0.2 million, representing open foreign currency exchange contracts, will be realized in earnings during the year ending December 31, 2024 if spot rates in the future are consistent with market rates as of March 31, 2024. The actual effect on earnings will be dependent on the actual spot rates when the forecasted transactions occur. We recognize derivative gains and losses in the “Cost of sales” line in the condensed consolidated statements of operations. Derivatives Not Designated As Cash Flow Hedging Instruments We hold certain forward contracts that have not been designated as cash flow hedging instruments for accounting purposes. Contracts used to hedge the exposure to foreign currency fluctuations associated with certain monetary assets and liabilities are not designated as cash flow hedging instruments and changes in the fair value of these items are recorded in earnings. We had open forward contracts not designated as cash flow hedging instruments for accounting purposes with various expiration dates to buy, sell or exchange foreign currencies with a U.S. dollar equivalent of approximately $87.1 million as of March 31, 2024. Fair Value of Derivative Instruments The following table provides the gross fair value and net balance sheet presentation of our derivative instruments. The Company had no open derivative cash flow hedge contracts as of December 31, 2023. March 31, 2024 Gross Amount of Derivatives (in Millions) Designated as Cash Flow Hedges Derivative assets Foreign exchange contracts $ 0.2  Total derivative assets (1) 0.2  Net derivative assets $ 0.2  __________________ 1.Net balance is included in “Prepaid and other current assets” in the condensed consolidated balance sheets. The following tables summarize the gains or losses related to our cash flow hedges and derivatives not designated as cash flow hedging instruments. Derivatives in Cash Flow Hedging Relationships (in Millions) Total Foreign Exchange Contracts Accumulated other comprehensive income, net of tax as of December 31, 2023 $ —  Unrealized hedging gains, net of tax 0.2  Total derivatives instruments impact on comprehensive income, net of tax 0.2  Accumulated other comprehensive income, net of tax as of March 31, 2024 $ 0.2  (in Millions) Total Foreign Exchange Contracts Accumulated other comprehensive income, net of tax as of December 31, 2022 $ —  Unrealized hedging gains, net of tax 0.2  Total derivatives instruments impact on comprehensive income, net of tax 0.2  Accumulated other comprehensive income, net of tax as of March 31, 2023 $ 0.2  Derivatives Not Designated as Cash Flow Hedging Instruments Location of Gain or (Loss) Recognized in Income on Derivatives Amount of Pre-tax Gain or (Loss)  Recognized in Income on Derivatives (1) Three Months Ended March 31, (in Millions)   2024 2023 Foreign Exchange contracts Other gain $ 13.9  $ —  Foreign Exchange contracts Cost of sales (3.3) 2.1  Total $ 10.6  $ 2.1  ____________________ 1.Amounts represent the gain or loss on the derivative instrument offset by the gain or loss on the hedged item. Fair Value Measurements Recurring Fair Value Measurements The following tables present our fair-value hierarchy for those assets and liabilities measured at fair-value on a recurring basis in our condensed consolidated balance sheets. (in Millions) March 31, 2024 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Investments in deferred compensation plan (1) $ 6.0  $ 6.0  $ —  $ —  JEMSE Receivable 5.5  —  —  5.5  Equity securities (2) 2.5  2.5  —  —  Derivatives – Foreign exchange 0.2  —  0.2  —  Total Assets $ 14.2  $ 8.5  $ 0.2  $ 5.5  Liabilities Deferred compensation plan obligation (3) $ 7.2  $ 7.2  $ —  $ —  Total Liabilities $ 7.2  $ 7.2  $ —  $ —    (in Millions) December 31, 2023 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Investments in deferred compensation plan (1) $ 4.1  $ 4.1  $ —  —  Total Assets $ 4.1  $ 4.1  $ —  $ —  Liabilities Deferred compensation plan obligation (3) $ 6.7  $ 6.7  $ —  $ —  Total Liabilities (4) $ 6.7  $ 6.7  $ —  $ —  ____________________ 1.Balance is included in “Investments” in the condensed consolidated balance sheets. Arcadium NQSP investments in Arcadium ordinary shares are recorded as "Treasury shares" in the condensed consolidated balance sheets and carried at historical cost. Mark-to-market gains of $0.8 million were recorded for the three months ended March 31, 2024 and mark-to-market losses of $0.2 million were recorded for the three months ended March 31, 2023, related to the Arcadium ordinary shares. The mark-to-market gains and losses were recorded in "Selling, general and administrative expenses" in the condensed consolidated statements of operations, with a corresponding offset to the deferred compensation plan obligation in the condensed consolidated balance sheets. 2.Mark-to-market gains and losses are recorded to "Other gain/loss" in the condensed consolidated statement of operations. 3.Balance is included in “Other long-term liabilities” in the condensed consolidated balance sheets. 4.The Company had no open cash flow hedge contracts as of December 31, 2023.

v3.24.1.1.u2

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Contingencies We are a party to various legal proceedings, certain of these matters are discussed below. Arcadium records liabilities for estimated losses from contingencies when information available indicates that a loss is probable and the amount of the loss, or range of loss, can be reasonably estimated. As additional information becomes available, management adjusts its assessments and estimates. Legal costs are expensed as incurred. In addition to the legal proceedings noted below, we have certain contingent liabilities arising in the ordinary course of business. Some of these contingencies are known but are so preliminary that the merits cannot be determined, or if more advanced, are not deemed material based on current knowledge; and some are unknown - for example, claims with respect to which we have no notice or claims which may arise in the future from products sold, guarantees or warranties made, or indemnities provided. Therefore, we are unable to develop a reasonable estimate of our potential exposure of loss for these contingencies, either individually or in the aggregate, at this time. There can be no assurance that the outcome of these contingencies will be favorable, and adverse results in certain of these contingencies could have a material adverse effect on the consolidated financial position, results of operations in any one reporting period, or liquidity. Argentine Customs & Tax Authority Matters Minera del Altiplano SA, our subsidiary in Argentina ("MdA"), has received notices from the Argentine Customs Authorities that they are conducting customs audits in Salta (for 2015 to 2019, 2021 and 2022), Rosario (for 2016 and 2017), Buenos Aires and Ezeiza (for 2018, 2019, 2021 and 2022) regarding the export of lithium carbonate by MdA from each of those locations. See Note 20 for more information about the payment the Company made in June 2023 for export duties and interest claimed by the Customs Authorities of Buenos Aires, Ezeiza and Salta related to exports made between the years 2018 – 2022. MdA was also notified from the Argentine Tax Authority of the start of transfer pricing audits for the periods 2017 and 2018. SDJ SA, our subsidiary in Argentina, received notification from Jujuy provincial tax authority regarding a royalty adjustment in favor of the Province for the periods 2021 and 2022. SDJ SA was also notified by the Argentine Tax Authority of the start of a transfer pricing audit for the period of 2018. A range of reasonably possible liabilities, if any, cannot be currently estimated by the Company. In January, 2023, the Argentina Ministry of Economy issued a resolution to cancel an export rebate regime relating to lithium products, which was followed by Presidential Decree No. 57/2023 in February, 2023. The Presidential Decree prospectively cancels all export rebates for lithium products. Prior to the Presidential Decree, MdA had the right to collect 4% of the FOB value for exported products (which consisted of the "La Puna" rebate which was 2.5% and the "Export" rebate which was 1.5%). In October 2023 by Presidential Decree No. 557/2023 the Export rebate of 1.5% was reinstated. Subsequent to the Presidential Decree entering into force on October 26, 2023 MdA is entitled to the 1.5% rebate/refund on FOB value of its exported products. As of March 31, 2024, MdA has a receivable of approximately $4.5 million USD which is still valid and remains in force after the Presidential Decrees. Australia Tax Matters We were informed on April 16, 2024 that the Australian Taxation Office will be performing a combined assurance review of Allkem Limited and its Australian subsidiaries for the period of July 1, 2019 to June 30, 2023. Leases All of our leases are operating leases as of March 31, 2024 and December 31, 2023. We have operating leases for corporate offices, manufacturing facilities, and land. Our leases have remaining lease terms of two to twenty-seven years. The Company assumed an ROU asset and corresponding lease liability of $53.4 million in the Allkem Livent Merger, all of which are accounted for as operating leases. Quantitative disclosures about our leases are summarized in the table below. Three Months Ended March 31, (in Millions, except for weighted-average amounts) 2024 2023 Lease Cost Operating lease cost $ 4.3  $ 0.3  Short-term lease cost 0.1  0.1  Total lease cost (1) $ 4.4  $ 0.4  Other information Cash paid for amounts included in the measurement of lease liabilities: Cash paid for operating leases $ 4.4  $ 0.3  __________________________ 1.Lease expense is classified as "Selling, general and administrative expenses" in our condensed consolidated statements of operations. As of March 31, 2024, our operating leases had a weighted average remaining lease term of 7.9 years and a weighted average discount rate of 8.4%. The table below presents a maturity analysis of our operating lease liabilities for each of the next five years and a total of the amounts for the remaining years. (in Millions) Undiscounted cash flows Remainder of 2024 $ 11.9  2025 10.0  2026 9.1  2027 8.4  2028 8.0  Thereafter 31.0  Total future minimum lease payments 78.4  Less: Imputed interest (23.3) Total $ 55.1

v3.24.1.1.u2

Supplemental Information	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Information	Supplemental Information The following tables present details of prepaid and other current assets, other assets, accrued and other current liabilities, and other long-term liabilities as presented on the condensed consolidated balance sheets: (in Millions) March 31, 2024 December 31, 2023 Prepaid and other current assets Tax related items $ 71.8  $ 29.5  Prepaid expenses 30.8  16.9  Argentina government receivable (1) 9.8  7.9  Other receivables 47.6  28.2  Bank Acceptance Drafts (2) 0.6  —  Derivative assets (Note 17) 0.2  —  Other current assets 4.9  3.9  Total $ 165.7  $ 86.4  (in Millions) March 31, 2024 December 31, 2023 Other assets Argentina government receivable (1), (3) $ 80.4  $ 71.3  Advance to contract manufacturers (4) 26.8  27.6  Long-term semi-finished goods inventory 192.2  1.0  Tax related items 4.2  4.0  Capitalized software, net 1.7  1.1  Investment in transit - Nemaska Lithium (5) 39.1  —  Other assets 97.7  22.7  Total $ 442.1  $ 127.7  _________________ 1.We have various subsidiaries that conduct business in Argentina. As of March 31, 2024 and December 31, 2023, $39.4 million and $38.8 million, respectively, of outstanding receivables due from the Argentina government, which primarily represent export tax and export rebate receivables, was denominated in U.S. dollars. A recent judicial decision relating to the U.S. dollar-denominated export tax receivable portion ($34.8 million) permits the Argentina government to reimburse us in Argentine pesos at the historical foreign exchange rate applicable at each past payment date, adjusted by a bank deposit interest rate. While Arcadium filed an appeal on November 6, 2023 and believes it has valid defenses on the technical merits, the ultimate resolution of this matter could result in a possible loss of up to $34.3 million. We continually review the recoverability of all outstanding receivables by analyzing historical experience, current collection trends and regional business and political factors among other factors. 2.Bank Acceptance Drafts are a common Chinese finance note used to settle trade transactions. The Company accepts these notes from Chinese customers based on criteria intended to ensure collectability and limit working capital usage. 3.In June 2023, the Company decided to pay $21.7 million for the export duties and interest claimed by the Customs Authorities of Buenos Aires, Ezeiza and Salta related to exports made between the years 2018 – 2022 registered in those locations. This payment stops the accrual of any further interest. It was a deposit made under protest and was not an admission of any of the claims made by the Customs Authorities or a waiver of any of the Company's defenses, including recovery of the deposit plus interest. The cases remain in discussion. See Note 19 for more information. 4.We record deferred charges for certain contract manufacturing agreements which we amortize over the term of the underlying contract. 5.Represents the Company's cash contributed to Nemaska Lithium in the first quarter of 2024 which, due to quarter-lag reporting, are not yet recorded in our consolidation of Nemaska. The balance is recorded to Other assets - noncurrent because the cash is expected to be used by Nemaska primarily for capital expenditures. See Note 9 for details. (in Millions) March 31, 2024 December 31, 2023 Accrued and other current liabilities Accrued payroll $ 32.4  $ 31.2  Retirement liability - 401k 5.0  3.2  Environmental reserves, current 2.6  0.5  Severance 5.6  1.7  Accrued investment in unconsolidated affiliates —  27.0  Other accrued and other current liabilities (1) 81.0  73.2  Total $ 126.6  $ 136.8  (in Millions) March 31, 2024 December 31, 2023 Other long-term liabilities Deferred compensation plan obligation $ 7.2  $ 6.7  Contingencies related to uncertain tax positions (2) 15.8  6.2  Self-insurance reserves 1.1  1.1  Asset retirement obligations 12.5  3.7  Other long-term liabilities 56.6  3.6  Total $ 93.2  $ 21.3  ____________________ 1.Amounts primarily include accrued capital expenditures related to our expansion projects. 2.As of March 31, 2024, we have recorded a liability for uncertain tax positions of $15.4 million and a $0.4 million indemnification liability where the offsetting uncertain tax position is with FMC, per the tax matters agreement.

v3.24.1.1.u2

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 15.6	$ 114.8	[1]
[1] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem.

v3.24.1.1.u2

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024 shares
Trading Arrangements, by Individual
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Sara Ponessa [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Sara Ponessa, the Company’s General Counsel and Secretary, adopted a trading plan that is intended to satisfy the affirmative defense of Rule 10b5-1(c) and complies with the requirements of Rule 10b5-1 (the “Ponessa Sales Plan”) to sell an aggregate of 64,161 shares upon the exercise of share options held by Ms. Ponessa under the Company’s share compensation plans and 70,000 shares from shares held on deposit in Ms. Ponessa's account. The Ponessa Sales Plan was adopted on March 4, 2024, with sales commencing under the Ponessa Sales Plan on June 5, 2024. The Ponessa Sales Plan terminates on the earliest to occur of (a) the close of business on January 15, 2025; (b) execution of all trades or expiration of all of the orders relating to such trades as specified in the Ponessa Sales Plan; (c) the date that the broker receives notice of liquidation, dissolution, bankruptcy, insolvency, or death of Ms. Ponessa; (d) when the broker receives notice from Ms. Ponessa of her termination of the Ponessa Sales Plan; (e) when the broker determines, in its sole discretion, that the Ponessa Sales Plan has been terminated, including, without limitation, where the broker determines there has been a modification or change to the Ponessa Sales Plan that constitutes the termination of the Ponessa Sales Plan; (f) the date the broker notifies Ms. Ponessa of the broker’s termination of the Ponessa Sales Plan due to Ms. Ponessa’s breach of any of the terms of the Ponessa Sales Plan or in the event that Ms. Ponessa trades shares outside of the Ponessa Sales Plan; or (g) where the broker exercises any other termination right it may have under the Ponessa Sales Plan.
Name	Sara Ponessa
Title	General Counsel and Secretary
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 4, 2024
Arrangement Duration	224 days
Paul Graves [Member]
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Paul Graves, the Company’s President, Chief Executive Officer and Director, adopted a trading plan that is intended to satisfy the affirmative defense of Rule 10b5-1(c) and complies with the requirements of Rule 10b5-1 (the “Graves Sales Plan”) to sell an aggregate of 234,038 shares upon the exercise of share options held by Mr. Graves under the Company’s share compensation plans and 100,000 shares from shares held on deposit in Mr. Graves' account. The Graves Sales Plan was adopted on March 27, 2024, with sales commencing under the Graves Sales Plan on July 1, 2024. The Graves Sales Plan terminates on the earliest to occur of (a) the close of business on December 31, 2025; (b) execution of all trades or expiration of all of the orders relating to such trades as specified in the Graves Sales Plan; (c) the date that the broker receives notice of liquidation, dissolution, bankruptcy, insolvency, or death of Mr. Graves; (d) when the broker receives notice from Mr. Graves of his termination of the Graves Sales Plan; (e) when the broker determines, in its sole discretion, that the Graves Sales Plan has been terminated, including, without limitation, where the broker determines there has been a modification or change to the Graves Sales Plan that constitutes the termination of the Graves Sales Plan; (f) the date the broker notifies Mr. Graves of the broker’s termination of the Graves Sales Plan due to Mr. Grave’s breach of any of the terms of the Graves Sales Plan or in the event that Mr. Graves trades shares outside of the Graves Sales Plan; or (g) where the broker exercises any other termination right it may have under the Graves Sales Plan.
Name	Paul Graves
Title	President, Chief Executive Officer and Director
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	March 27, 2024
Arrangement Duration	548 days
Sara Ponessa Trading Arrangement, Share Options [Member] | Sara Ponessa [Member]
Trading Arrangements, by Individual
Aggregate Available	64,161
Sara Ponessa Trading Arrangement, Shares Held on Deposit [Member] | Sara Ponessa [Member]
Trading Arrangements, by Individual
Aggregate Available	70,000
Paul Graves Trading Arrangement, Share Options [Member] | Paul Graves [Member]
Trading Arrangements, by Individual
Aggregate Available	234,038
Paul Graves Trading Arrangement, Shares Held on Deposit [Member] | Paul Graves [Member]
Trading Arrangements, by Individual
Aggregate Available	100,000

v3.24.1.1.u2

Significant Accounting Policies and Related Financial Information (Policies)	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principal Accounting Policies and Related Financial Information	The accompanying condensed consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission ("SEC") for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. GAAP have been condensed or omitted from these interim financial statements.
Segment information	Segment Information In January 2024, Arcadium Lithium completed the Allkem Livent Merger. See Note 4, Allkem Livent Merger for further details. Following the closing of the Allkem Livent Merger, we currently operate as one reportable segment based on the commonalities among our products and services. As integration evolves, we will continue to assess this determination.
Revenue Recognition	Revenue Recognition Revenue from product sales is recognized when we satisfy a performance obligation by transferring the promised goods to a customer, that is, when control of the good transfers to the customer. Payment terms generally range from 20 to 180 days. In determining when the control of goods is transferred, we typically assess, among other things, the transfer of title and risk of loss and the shipping terms of the contract. We record amounts billed for shipping and handling fees as revenue. Costs incurred for shipping and handling are recorded in cost of sales. When we perform shipping and handling activities after the transfer of control to the customer (e.g., when control transfers prior to delivery), they are considered fulfillment activities, and accordingly, the costs are accrued to cost of sales when the related revenue is recognized. Amounts billed for sales and use taxes, VAT, and certain excise and other specific transactional taxes imposed on revenue-producing transactions are presented on a net basis and excluded from revenue in the condensed consolidated statements of operations. We record a liability until remitted to the respective taxing authority. We satisfy our obligations by transferring goods and services in exchange for consideration from customers. The timing of performance sometimes differs from the timing the associated consideration is received from the customer, thus resulting in the recognition of a contract asset or liability. These may arise from provisional pricing within certain of our customer contracts, or if the customer’s payment of consideration is received prior to completion of our related performance obligation. Provisional pricing results in variable consideration which we estimate by using an expected value method taking into account all information that is reasonably available including publicly available pricing forecasts. We only include variable consideration within the transaction price to the extent that it is probable that a significant reversal in the amount of revenue recognized will not occur. Performance obligations Occasionally, we may enter into multi-year take or pay supply agreements with customers. The aggregate amount of revenue expected to be recognized related to these contracts’ performance obligations is approximately $1.8 billion in the next five years. Based on our past experience with the customers under these arrangements, we expect to continue recognizing revenue in accordance with the contracts as we transfer control of the product to the customer. However, in the case a shortfall of volume purchases occurs, we will recognize the amount payable by the customer over the remaining performance obligations in the contract.
Equity method investments	Equity method investments We stop applying the equity method when we have reduced the value of our equity method investment, commitments and additional investments (i.e., loans or advances) in the investee to zero. If the investee subsequently reports net income, we resume applying the equity method when our share of that net income is equal to the suspended losses (i.e., our share of the investee's net losses not previously recognized). If facts and circumstances indicate that a decrease in value of the investment has occurred that is other than temporary, we recognize an impairment loss equal to an amount by which the carrying amount exceeds the fair value of the equity method investment.
Goodwill	Goodwill The Company accounts for goodwill and other intangibles acquired in a business combination in conformity with current accounting guidance that requires that goodwill and indefinite-lived intangible assets not be amortized. Under the guidance, goodwill is tested for impairment by comparing the estimated fair value of reporting units to the related carrying value. Reporting units are either operating business segments or one level below operating business segments for which discrete financial information is available and for which operating results are regularly reviewed by the business management. In applying the goodwill impairment test, a qualitative test ("Step 0") is initially performed, under which qualitative factors are assessed to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. Qualitative factors may include, but are not limited to, economic conditions, industry and market considerations, cost factors, overall financial performance of the reporting units and other entity and reporting unit specific events. If after assessing these qualitative factors, it is determined that it is "more-likely-than-not" that the fair value of the reporting unit is less than the carrying value, a quantitative test ("Step 1") is performed. During Step 1, the fair value is estimated using a discounted cash flow model.
Asset Retirement Obligations	Asset Retirement Obligations The Company accounts for asset retirement obligations ("AROs") in accordance with ASC 410-20, Asset Retirement Obligations "ASC 410-20". We record AROs at present value at the time the liability is incurred if we can reasonably estimate the settlement date. The associated AROs are capitalized as part of the carrying amount of related long-lived assets. In future periods, the liability is accreted to its present value and the capitalized cost is depreciated over the useful life of the related asset. We also adjust the liability for changes resulting from the passage of time and/or revisions to the timing or the amount of the original estimate. Upon retirement of the long-lived asset, we either settle the obligation for its recorded amount.
Mine Development Costs and Mineral Interests	Mine Development Costs Mine development costs include: a) exploration and evaluation ("E&E") expenditures incurred during the search for mineral resources as well as the determination of the technical feasibility and commercial viability of extracting the mineral resource; and b) stripping costs of removing overburden and waste materials to access the mineral body at an open pit mine. The Company capitalizes E&E expenditures to PP&E under a successful efforts basis when proven and probable reserves are established for the sites where E&E activities are being performed. E&E assets recognized as part of business combinations are also capitalized. All other E&E expenditures are expensed. Stripping costs incurred prior to the production phase are capitalized to PP&E during the development of an open pit mine. When multiple open pits exist at a mining complex utilizing common processing facilities, such pre-production stripping costs are capitalized at each pit. The removal, production, and sale of de minimis saleable materials may occur during the development phase of an open pit mine and are assigned incremental mining costs related to the removal of that material. The production phase of an open pit mine commences when saleable minerals, beyond a de minimis amount, are produced. Stripping costs incurred during the production phase of a mine are variable production costs that are included as a component of inventory to be recognized in Cost of Sales in the same period as the revenue from sale of that inventory. Capitalized mine development costs are amortized using the units-of-production method based on estimated recoverable minerals in proven and probable reserves, and are amortized over the estimated life of the mineral body. Mineral Interests Mineral interests include acquired interests in production, development and exploration stage properties. Mineral interests are capitalized at their fair value at the acquisition date, either as an individual asset purchase or as part of a business combination. Mineral interests in the development and exploration stage are not amortized until the underlying property is converted to the production stage, at which point the mineral interests are amortized over the estimated recoverable proven and probable reserves using a units-of-production method.
Recently Issued and Adopted Accounting Pronouncements and Regulatory Items	In December 2023, the Financial Accounting Standard Board ("FASB") issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This ASU enhances existing income tax disclosures to better assess how an entity's operation and related tax risks, tax planning, and operational opportunities affect its tax rate and prospects for future cash flows. The ASU is effective for annual periods beginning after December 15, 2024. We are currently evaluating the effect the guidance will have on our condensed consolidated financial statements. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280). This ASU improves reportable segment disclosure requirements, primarily through enhanced disclosures related to significant segment expenses. The ASU is effective for annual periods beginning after December 15, 2023, and interim periods beginning after December 15, 2024. We are currently evaluating the effect the guidance will have on our condensed consolidated financial statements.

v3.24.1.1.u2

Allkem Livent Merger (Tables)	3 Months Ended
	Mar. 31, 2024
Business Combination and Asset Acquisition [Abstract]
Schedule of Consideration Transferred	The Acquisition Date fair value of consideration transferred consisted of the following: (in millions) Amount Consideration: Fair value of Arcadium ordinary shares issued to Allkem shareholders $ 4,385.6  Fair value of converted Allkem performance rights attributable to pre-combination service 4.8  Total consideration $ 4,390.4
Schedule of Purchase Price Allocation	The following table summarizes the preliminary purchase price allocation for the Allkem Livent Merger as of January 4, 2024, which is subject to change: (in Millions, except per share amounts) Amount Total consideration $ 4,390.4  Assets acquired: Cash and cash equivalents $ 681.4  Trade receivables 64.2  Inventories 121.3  Prepaid and other current assets 87.2  Property, plant and equipment 4,325.5  Right of use assets - operating leases, net 53.4  Deferred income tax assets 26.3  Other assets (1) 192.9  Total assets acquired $ 5,552.2  Liabilities assumed: Accounts payable, trade and other $ 221.9  Accrued and other current liabilities 35.1  Income taxes 78.8  Long-term debt including current portion 301.7  Operating lease liabilities - long-term 53.4  Environmental liabilities 18.9  Deferred income tax liabilities 1,316.7  Other long-term liabilities 49.5  Total liabilities assumed $ 2,076.0  Fair value of net assets acquired $ 3,476.2  Add: Fair value of noncontrolling interests acquired 275.0  Fair value of net assets acquired less noncontrolling interests acquired $ 3,201.2  Goodwill $ 1,189.2  ___________________ 1.Includes long-term semi-finished goods inventory.
Schedule of Pro Forma Information	The following table represents Allkem's revenues and net earnings included in Arcadium's condensed consolidated statements of operations from the Acquisition Date through March 31, 2024. (in Millions) Three Months Ended March 31, 2024 Revenue $ 102.5  Income from operations before income taxes $ 78.2  The unaudited pro forma financial results are as follows: (in Millions) Three Months Ended March 31, 2023 (Unaudited) Revenue $ 569.4  Net income $ 234.1

v3.24.1.1.u2

Goodwill (Tables)	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table summarizes the changes in goodwill for the three months ended March 31, 2024. (in Millions) Allkem Nemaska Lithium Total Balance as of December 31, 2023 $ —  $ 120.7  $ 120.7  Acquisitions - Allkem Livent Merger 1,189.2  —  1,189.2  Balance as of March 31, 2024 $ 1,189.2  $ 120.7  $ 1,309.9  See Note 4 for further details.

v3.24.1.1.u2

Revenue Recognition (Tables)	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table provides information about disaggregated revenue by major geographical region: (in Millions) Three Months Ended March 31, 2024 2023 Asia Pacific (1) $ 220.1  $ 167.0  North America (1) 20.7  51.9  Europe, Middle East & Africa 19.6  32.8  Latin America 0.8  1.8  Consolidated Revenue $ 261.2  $ 253.5  1.During the three months ended March 31, 2024, countries with sales in excess of 10% of consolidated revenue consisted of China, Japan, and South Korea. Sales for the three months ended March 31, 2024 for China, Japan, and South Korea totaled $125.9 million, $46.0 million, and $45.5 million, respectively. During the three months ended March 31, 2023, countries with sales in excess of 10% of consolidated revenue consisted of China, the U.S., South Korea, and Japan. Sales for the three months ended March 31, 2023 for China, the U.S., South Korea, and Japan totaled $88.4 million, $50.2 million, and $35.1 million, and $33.4 million, respectively. The following table provides information about disaggregated revenue by major product category: (in Millions) Three Months Ended March 31, 2024 2023 Lithium Hydroxide $ 110.6  $ 152.7  Lithium Carbonate (1) 79.8  9.5  Butyllithium and Other Lithium Specialties 46.0  91.3  Spodumene Concentrate (2) 24.8  —  Consolidated Revenue $ 261.2  $ 253.5  ______________________ 1.Includes lithium carbonate by-product revenue. 2.Includes low-grade spodumene sales and minimal other products.
Schedule of Receivables and Contract Liabilities	The following table presents the opening and closing balances of our contract liabilities and current trade receivables, net of allowances from contracts with customers. (in Millions) Balance as of March 31, 2024 Balance as of December 31, 2023 (Decrease)/increase Receivables from contracts with customers, net of allowances $ 93.5  $ 106.7  $ (13.2) Contract liability - short-term 30.6  4.4  26.2  Contract liability - long-term 218.3  217.8  0.5

v3.24.1.1.u2

Inventories, Net (Tables)	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories consisted of the following:  (in Millions) March 31, 2024 December 31, 2023 Finished goods $ 114.1  $ 59.1  Semi-finished goods 122.2  108.8  Raw materials, supplies, and other 92.5  49.6  Inventory, net $ 328.8  $ 217.5

v3.24.1.1.u2

Investments (Tables)	3 Months Ended
	Mar. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Investments in and Advances to Affiliates, Schedule of Investments	Investments consisted of the following:  (in Millions) March 31, 2024 December 31, 2023 ESM ILiAD, LLC $ 30.1  $ 30.1  Arcadium NQSP 6.0  4.7  Other 2.5  —  Investments $ 38.6  $ 34.8

v3.24.1.1.u2

Property, Plant and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	Property, plant and equipment consisted of the following: (in Millions) March 31, 2024 December 31, 2023 Land and land improvements $ 325.2  $ 106.2  Buildings 724.5  134.9  Machinery and equipment 791.6  420.7  Mineral rights 3,278.0  560.0  Construction in progress 1,953.5  1,284.4  Total cost $ 7,072.8  $ 2,506.2  Accumulated depreciation (279.1) (269.1) Property, plant and equipment, net $ 6,793.7  $ 2,237.1  The major classifications of property, equipment and software, including their respective principal depreciation and amortization method and expected useful lives, consisted of the following: Asset type Depreciation and amortization method Useful Life Land N/A — Land improvements Straight-line 20 years Buildings Straight-line 20-40 years Mineral rights Units-of-production Based on rate of depletion of reserves Mining extraction equipment Units-of-production Based on rate of depletion of reserves Leased plant and equipment Straight-line Lease period (1-10.5 years) Other machinery and equipment Straight-line 3-18 years Software Straight-line 3-10 years

v3.24.1.1.u2

Restructuring and Other Charges (Tables)	3 Months Ended
	Mar. 31, 2024
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Charges and Asset Disposals	The following table shows other charges included in "Restructuring and other charges" in the condensed consolidated statements of operations: Three Months Ended March 31, (in Millions) 2024 2023 Restructuring charges: Severance-related and exit costs $ 10.9  $ 1.7  Other charges: Costs related to the Allkem Livent Merger 67.0  —  Other 5.7  0.2  Total Restructuring and other charges $ 83.6  $ 1.9

v3.24.1.1.u2

Debt (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of Long-Term Debt	Long-term debt consists of the following: Interest Rate Percentage Maturity Date March 31, 2024 December 31, 2023 (in Millions) SOFR borrowings Base rate borrowings Revolving Credit Facility (1) 7.18% 9.25% 2027 $ —  $ —  4.125% Convertible Senior Notes due 2025 4.125% 2025 245.8  245.8  Transaction costs - 2025 Notes (2.0) (2.4) Nemaska - Prepayment agreement (2) 8.9% 75.0  75.0  Discount - Prepayment agreement (20.2) (19.8) Nemaska - Other 0.4  3.4  Debt assumed in Allkem Livent Merger Project Loan Facility - Stage 1 of Olaroz Plant 4.896% 2024 9.2  —  Project Loan Facility - Stage 2 of Olaroz Plant 2.612% 2029 144.0  —  Project Financing Facility - Sal de Vida 10.051% 2030 47.0  —  Affiliate Loans with TTC 11.331% 2030 81.6  —  Affiliate Loan with TLP 10.34% 2026 2.5  —  Total debt assumed in Allkem Livent Merger 284.3  —  Subtotal long-term debt (including current maturities) 583.3  302.0  Less current maturities $ (80.6) $ (2.4) Total long-term debt $ 502.7  $ 299.6  ______________________________ 1.As of March 31, 2024 and December 31, 2023, there were $15.5 million in letters of credit outstanding under our Revolving Credit Facility and $484.5 million available funds. Fund availability is subject to the Company meeting its debt covenants. 2.Represents first advance payment in connection with customer supply agreement repayable in equal quarterly installments beginning in January 2027 and ending in October 2031. Represents U.S. GAAP imputed interest rate. On March 28, 2024, Nemaska Lithium received a second advance payment of $150 million in connection with the customer supply agreement, with a discount of $52.2 million.

v3.24.1.1.u2

Share-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan	We recognized the following share compensation expense for Legacy Livent Awards and awards under the Arcadium Plan: Three Months Ended March 31, (in Millions) 2024 Share Option Expense, net of taxes of $0.1 $ 0.4  Restricted Share Expense, net of taxes of $0.7 12.4  Performance-Based Restricted Share Expense, net of taxes of less than $0.1 0.4  Total Share Compensation Expense, net of taxes of $0.8 (1) $ 13.2  ____________________  (1)    Gross share compensation charges of $2.3 million and $13.5 million were recorded to "Selling, general and administrative expenses" and "Restructuring and other charges", respectively, in our condensed consolidated statements of operations for the three months ended March 31, 2024.
Schedule of Black Scholes Valuation Assumptions for Stock Option Grants	Black Scholes valuation assumptions for Arcadium Plan share option grants:  Three Months Ended March 31, 2024 Expected dividend yield —% Expected volatility 31.18% Expected life (in years) 6.0 Risk-free interest rate 4.08%
Summary of Stock Option Activity	The following summary shows share option activity for the Allkem Livent Merger and the Arcadium Plan for the three months ended March 31, 2024: Number of Options Granted But Not Exercised Weighted-Average Remaining Contractual Life (in Years) Weighted-Average Exercise Price Per Share Aggregate Intrinsic Value (in Millions) Outstanding December 31, 2023 5,060,687  5.6 years $ 6.73  $ 6.5  Granted 2,517,175  $ 4.95  Exercised (53,056) $ 4.05  $ —  Outstanding March 31, 2024 7,524,806  6.6 $ 6.28  $ 0.8  Exercisable at March 31, 2024 4,142,996  4.9 $ 6.25  $ 0.8
Summary of Restricted Award Activity	The following table shows RSU activity for the Allkem Livent Merger and the Arcadium Plan for the three months ended March 31, 2024: Restricted Share Units Number of awards Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value (in Millions) Nonvested December 31, 2023 2,287,088  $ 7.83  $ 17.1  Granted (1) 2,238,079  $ 5.99  Vested (2) (1,816,439) $ 7.11  Nonvested March 31, 2024 2,708,728  $ 6.83  $ 10.5  ___________________ 1.The Company granted 1,080,825 Allkem Replacement Awards on January 12, 2024 pursuant to the Transaction Agreement. 2.Immediately prior to the Acquisition Date, 768,440 non-employee Director RSUs vested and were paid out in cash of $5.3 million pursuant to the Transaction Agreement. The following table shows PRSU activity for the three months ended March 31, 2024. Performance-Based Restricted Share Units Number of awards Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value (in Millions) Nonvested as of December 31, 2023 96,885  $ 9.43  $ 0.7  Vested (96,885) $ 9.43  Nonvested as of March 31, 2024 —  $ —  $ —

v3.24.1.1.u2

Equity (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Schedule of Common Stock Issued and Outstanding	The following is a summary of Arcadium's ordinary shares issued and outstanding: Issued Treasury Outstanding Balance as of December 31, 2023 (1) 433,059,946  (263,669) 432,796,277  Issued to Allkem shareholders - Allkem Livent Merger 641,337,840  —  641,337,840  PRSU and RSU awards accelerated - Allkem Livent Merger 648,969  —  648,969  Arcadium RSU awards 15,248  —  15,248  Arcadium share option awards 8,497  —  8,497  Net sales of treasury shares - Arcadium NQSP —  461  461  Balance as of March 31, 2024 1,075,070,500  (263,208) 1,074,807,292  _____________________ 1.Balances outstanding as of December 31, 2023, representing predecessor Livent, have been adjusted to reflect the 2.406 Exchange Ratio.
Schedule of Accumulated Other Comprehensive Income (Loss)	Summarized below is the roll forward of accumulated other comprehensive loss, net of tax. (in Millions) Foreign currency adjustments Derivative Instruments Total Accumulated other comprehensive loss, net of tax as of December 31, 2023 $ (49.8) $ —  $ (49.8) Other comprehensive (losses)/income before reclassifications (20.2) 0.2  (20.0) Accumulated other comprehensive loss, net of tax as of March 31, 2024 $ (70.0) $ 0.2  $ (69.8) (in Millions) Foreign currency adjustments Derivative Instruments Total Accumulated other comprehensive loss, net of tax as of December 31, 2022 $ (51.0) $ —  $ (51.0) Other comprehensive income before reclassifications 1.5  0.2  1.7  Accumulated other comprehensive loss, net of tax as of March 31, 2023 $ (49.5) $ 0.2  $ (49.3)

v3.24.1.1.u2

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Schedule of Calculation of Basic and Diluted Earnings Per Share	Earnings applicable to ordinary shares and ordinary shares used in the calculation of basic and diluted earnings per share are as follows: (in Millions, Except Share and Per Share Data) Three Months Ended March 31, 2024 2023 (1) Numerator: Net income attributable to Arcadium Lithium plc $ 15.6  $ 114.8  Denominator: Weighted average ordinary shares outstanding - basic 1,053.4  432.0  Dilutive share equivalents from share-based plans 1.0  3.6  Dilutive share equivalents from 2025 Notes 67.7  67.7  Weighted average ordinary shares outstanding - diluted 1,122.1  503.3  Basic earnings per ordinary share $ 0.01  $ 0.27  Diluted earnings per ordinary share $ 0.01  $ 0.23  _____________________ 1.For the three months ended March 31, 2023, weighted average ordinary shares outstanding - basic and diluted, dilutive share equivalents and basic and diluted earnings per ordinary share amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio.

v3.24.1.1.u2

Financial Instruments, Risk Management and Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Schedule Of Financial Instrument Valuation Methods	Our other financial instruments include the following: Financial Instrument Valuation Method Foreign exchange forward contracts Estimated amounts that would be received or paid to terminate the contracts at the reporting date based on current market prices for applicable currencies.
Schedule of Fair Value of Derivative Instruments	The following table provides the gross fair value and net balance sheet presentation of our derivative instruments. The Company had no open derivative cash flow hedge contracts as of December 31, 2023. March 31, 2024 Gross Amount of Derivatives (in Millions) Designated as Cash Flow Hedges Derivative assets Foreign exchange contracts $ 0.2  Total derivative assets (1) 0.2  Net derivative assets $ 0.2  __________________ 1.Net balance is included in “Prepaid and other current assets” in the condensed consolidated balance sheets.
Schedule of Derivatives in Cash Flow Hedging Relationships	The following tables summarize the gains or losses related to our cash flow hedges and derivatives not designated as cash flow hedging instruments. Derivatives in Cash Flow Hedging Relationships (in Millions) Total Foreign Exchange Contracts Accumulated other comprehensive income, net of tax as of December 31, 2023 $ —  Unrealized hedging gains, net of tax 0.2  Total derivatives instruments impact on comprehensive income, net of tax 0.2  Accumulated other comprehensive income, net of tax as of March 31, 2024 $ 0.2  (in Millions) Total Foreign Exchange Contracts Accumulated other comprehensive income, net of tax as of December 31, 2022 $ —  Unrealized hedging gains, net of tax 0.2  Total derivatives instruments impact on comprehensive income, net of tax 0.2  Accumulated other comprehensive income, net of tax as of March 31, 2023 $ 0.2
Schedule of Derivatives Not Designated as Cash Flow Hedging Instruments	Location of Gain or (Loss) Recognized in Income on Derivatives Amount of Pre-tax Gain or (Loss)  Recognized in Income on Derivatives (1) Three Months Ended March 31, (in Millions)   2024 2023 Foreign Exchange contracts Other gain $ 13.9  $ —  Foreign Exchange contracts Cost of sales (3.3) 2.1  Total $ 10.6  $ 2.1  ____________________ 1.Amounts represent the gain or loss on the derivative instrument offset by the gain or loss on the hedged item.
Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present our fair-value hierarchy for those assets and liabilities measured at fair-value on a recurring basis in our condensed consolidated balance sheets. (in Millions) March 31, 2024 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Investments in deferred compensation plan (1) $ 6.0  $ 6.0  $ —  $ —  JEMSE Receivable 5.5  —  —  5.5  Equity securities (2) 2.5  2.5  —  —  Derivatives – Foreign exchange 0.2  —  0.2  —  Total Assets $ 14.2  $ 8.5  $ 0.2  $ 5.5  Liabilities Deferred compensation plan obligation (3) $ 7.2  $ 7.2  $ —  $ —  Total Liabilities $ 7.2  $ 7.2  $ —  $ —    (in Millions) December 31, 2023 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Investments in deferred compensation plan (1) $ 4.1  $ 4.1  $ —  —  Total Assets $ 4.1  $ 4.1  $ —  $ —  Liabilities Deferred compensation plan obligation (3) $ 6.7  $ 6.7  $ —  $ —  Total Liabilities (4) $ 6.7  $ 6.7  $ —  $ —  ____________________ 1.Balance is included in “Investments” in the condensed consolidated balance sheets. Arcadium NQSP investments in Arcadium ordinary shares are recorded as "Treasury shares" in the condensed consolidated balance sheets and carried at historical cost. Mark-to-market gains of $0.8 million were recorded for the three months ended March 31, 2024 and mark-to-market losses of $0.2 million were recorded for the three months ended March 31, 2023, related to the Arcadium ordinary shares. The mark-to-market gains and losses were recorded in "Selling, general and administrative expenses" in the condensed consolidated statements of operations, with a corresponding offset to the deferred compensation plan obligation in the condensed consolidated balance sheets. 2.Mark-to-market gains and losses are recorded to "Other gain/loss" in the condensed consolidated statement of operations. 3.Balance is included in “Other long-term liabilities” in the condensed consolidated balance sheets. 4.The Company had no open cash flow hedge contracts as of December 31, 2023.

v3.24.1.1.u2

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Schedule of Lease Cost	Quantitative disclosures about our leases are summarized in the table below. Three Months Ended March 31, (in Millions, except for weighted-average amounts) 2024 2023 Lease Cost Operating lease cost $ 4.3  $ 0.3  Short-term lease cost 0.1  0.1  Total lease cost (1) $ 4.4  $ 0.4  Other information Cash paid for amounts included in the measurement of lease liabilities: Cash paid for operating leases $ 4.4  $ 0.3  __________________________ 1.Lease expense is classified as "Selling, general and administrative expenses" in our condensed consolidated statements of operations.
Schedule of Maturity Analysis of Operating Lease Liabilities	The table below presents a maturity analysis of our operating lease liabilities for each of the next five years and a total of the amounts for the remaining years. (in Millions) Undiscounted cash flows Remainder of 2024 $ 11.9  2025 10.0  2026 9.1  2027 8.4  2028 8.0  Thereafter 31.0  Total future minimum lease payments 78.4  Less: Imputed interest (23.3) Total $ 55.1

v3.24.1.1.u2

Supplemental Information (Tables)	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Prepaid and Other Assets	The following tables present details of prepaid and other current assets, other assets, accrued and other current liabilities, and other long-term liabilities as presented on the condensed consolidated balance sheets: (in Millions) March 31, 2024 December 31, 2023 Prepaid and other current assets Tax related items $ 71.8  $ 29.5  Prepaid expenses 30.8  16.9  Argentina government receivable (1) 9.8  7.9  Other receivables 47.6  28.2  Bank Acceptance Drafts (2) 0.6  —  Derivative assets (Note 17) 0.2  —  Other current assets 4.9  3.9  Total $ 165.7  $ 86.4  (in Millions) March 31, 2024 December 31, 2023 Other assets Argentina government receivable (1), (3) $ 80.4  $ 71.3  Advance to contract manufacturers (4) 26.8  27.6  Long-term semi-finished goods inventory 192.2  1.0  Tax related items 4.2  4.0  Capitalized software, net 1.7  1.1  Investment in transit - Nemaska Lithium (5) 39.1  —  Other assets 97.7  22.7  Total $ 442.1  $ 127.7  _________________ 1.We have various subsidiaries that conduct business in Argentina. As of March 31, 2024 and December 31, 2023, $39.4 million and $38.8 million, respectively, of outstanding receivables due from the Argentina government, which primarily represent export tax and export rebate receivables, was denominated in U.S. dollars. A recent judicial decision relating to the U.S. dollar-denominated export tax receivable portion ($34.8 million) permits the Argentina government to reimburse us in Argentine pesos at the historical foreign exchange rate applicable at each past payment date, adjusted by a bank deposit interest rate. While Arcadium filed an appeal on November 6, 2023 and believes it has valid defenses on the technical merits, the ultimate resolution of this matter could result in a possible loss of up to $34.3 million. We continually review the recoverability of all outstanding receivables by analyzing historical experience, current collection trends and regional business and political factors among other factors. 2.Bank Acceptance Drafts are a common Chinese finance note used to settle trade transactions. The Company accepts these notes from Chinese customers based on criteria intended to ensure collectability and limit working capital usage. 3.In June 2023, the Company decided to pay $21.7 million for the export duties and interest claimed by the Customs Authorities of Buenos Aires, Ezeiza and Salta related to exports made between the years 2018 – 2022 registered in those locations. This payment stops the accrual of any further interest. It was a deposit made under protest and was not an admission of any of the claims made by the Customs Authorities or a waiver of any of the Company's defenses, including recovery of the deposit plus interest. The cases remain in discussion. See Note 19 for more information. 4.We record deferred charges for certain contract manufacturing agreements which we amortize over the term of the underlying contract. 5.Represents the Company's cash contributed to Nemaska Lithium in the first quarter of 2024 which, due to quarter-lag reporting, are not yet recorded in our consolidation of Nemaska. The balance is recorded to Other assets - noncurrent because the cash is expected to be used by Nemaska primarily for capital expenditures. See Note 9 for details.
Schedule of Accrued and Other Liabilities	(in Millions) March 31, 2024 December 31, 2023 Accrued and other current liabilities Accrued payroll $ 32.4  $ 31.2  Retirement liability - 401k 5.0  3.2  Environmental reserves, current 2.6  0.5  Severance 5.6  1.7  Accrued investment in unconsolidated affiliates —  27.0  Other accrued and other current liabilities (1) 81.0  73.2  Total $ 126.6  $ 136.8  (in Millions) March 31, 2024 December 31, 2023 Other long-term liabilities Deferred compensation plan obligation $ 7.2  $ 6.7  Contingencies related to uncertain tax positions (2) 15.8  6.2  Self-insurance reserves 1.1  1.1  Asset retirement obligations 12.5  3.7  Other long-term liabilities 56.6  3.6  Total $ 93.2  $ 21.3  ____________________ 1.Amounts primarily include accrued capital expenditures related to our expansion projects. 2.As of March 31, 2024, we have recorded a liability for uncertain tax positions of $15.4 million and a $0.4 million indemnification liability where the offsetting uncertain tax position is with FMC, per the tax matters agreement.

v3.24.1.1.u2

Significant Accounting Policies and Related Financial Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)
Significant Accounting Policies [Line Items]
Number of reportable segments | segment	1
Asset retirement obligation	$ 12.5	$ 3.7
Realized foreign currency transaction gain	$ 29.6
Minimum
Significant Accounting Policies [Line Items]
Payment term (in days)	20 days
Maximum
Significant Accounting Policies [Line Items]
Payment term (in days)	180 days

v3.24.1.1.u2

Allkem Livent Merger - Narrative (Details) $ / shares in Units, $ in Millions		3 Months Ended
	Jan. 04, 2024 USD ($) $ / shares shares	Mar. 31, 2024 USD ($) $ / shares	Mar. 31, 2023 USD ($) $ / shares	Dec. 31, 2023 $ / shares	Dec. 31, 2022 $ / shares
Business Acquisition [Line Items]
Common stock, par value (in dollars per share) | $ / shares	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00
Costs related to the Allkem Livent Merger | $		$ 67.0	$ 0.0
Livent Corporation
Business Acquisition [Line Items]
Common stock, par value (in dollars per share) | $ / shares	$ 0.001
Allkem Livent Merger
Business Acquisition [Line Items]
Conversion ratio	2.406
Trade receivables | $	$ 64.2
Property, plant and equipment | $	4,325.5
Allkem Livent Merger | Mineral rights
Business Acquisition [Line Items]
Property, plant and equipment | $	2,745.0
Allkem Livent Merger | Non Mining Properties and Mineral Rights
Business Acquisition [Line Items]
Property, plant and equipment | $	$ 1,580.5
Allkem Livent Merger | Former Livent Stockholders
Business Acquisition [Line Items]
Number of shares issued in transaction (in shares) | shares	433,156,855
Allkem Livent Merger | Former Allkem Shareholders
Business Acquisition [Line Items]
Number of shares issued in transaction (in shares) | shares	641,337,840
Allkem Livent Merger | CHESS Depositary Instrument
Business Acquisition [Line Items]
Equity interest issued or issuable, share exchange ratio	1
Allkem Livent Merger | CHESS Depositary Instrument | Former Allkem Shareholders
Business Acquisition [Line Items]
Number of shares issued in transaction (in shares) | shares	542,612,224
Allkem Livent Merger | Ordinary Shares, $1.00 Per Share Par Value
Business Acquisition [Line Items]
Equity interest issued or issuable, share exchange ratio	1
Allkem Livent Merger | Ordinary Shares, $1.00 Per Share Par Value | Former Allkem Shareholders
Business Acquisition [Line Items]
Number of shares issued in transaction (in shares) | shares	98,725,616
Allkem Livent Merger | Performance Shares | Former Livent Stockholders
Business Acquisition [Line Items]
Number of shares issued in transaction (in shares) | shares	96,909

v3.24.1.1.u2

Allkem Livent Merger - Consideration Transferred (Details) - Allkem Livent Merger $ in Millions	Jan. 04, 2024 USD ($)
Business Acquisition [Line Items]
Fair value of Arcadium ordinary shares issued to Allkem shareholders	$ 4,385.6
Fair value of converted Allkem performance rights attributable to pre-combination service	4.8
Total consideration	$ 4,390.4

v3.24.1.1.u2

Allkem Livent Merger - Purchase Price Allocation (Details) - USD ($) $ in Millions	Jan. 04, 2024	Mar. 31, 2024	Dec. 31, 2023	[1]
Liabilities assumed:
Goodwill		$ 1,309.9	$ 120.7
Allkem Livent Merger
Business Acquisition [Line Items]
Total consideration	$ 4,390.4
Assets acquired:
Cash and cash equivalents	681.4
Trade receivables	64.2
Inventories	121.3
Prepaid and other current assets	87.2
Property, plant and equipment	4,325.5
Right of use assets - operating leases, net	53.4
Deferred income tax assets	26.3
Other assets	192.9
Total assets acquired	5,552.2
Liabilities assumed:
Accounts payable, trade and other	221.9
Accrued and other current liabilities	35.1
Income taxes	78.8
Long-term debt including current portion	301.7
Operating lease liabilities - long-term	53.4
Environmental liabilities	18.9
Deferred income tax liabilities	1,316.7
Other long-term liabilities	49.5
Total liabilities assumed	2,076.0
Fair value of net assets acquired	3,476.2
Add: Fair value of noncontrolling interests acquired	275.0
Fair value of net assets acquired less noncontrolling interests acquired	3,201.2
Allkem Livent Merger | Non Mining Properties and Mineral Rights
Assets acquired:
Property, plant and equipment	$ 1,580.5
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Allkem Livent Merger - Earnings Subsequent to the Closing Date of Transaction (Details) - Allkem Livent Merger $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Business Acquisition [Line Items]
Revenue	$ 102.5
Income from operations before income taxes	$ 78.2

v3.24.1.1.u2

Allkem Livent Merger - Pro Forma Information (Details) - Allkem Livent Merger $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($)
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenue	$ 569.4
Net income	$ 234.1

v3.24.1.1.u2

Goodwill (Details) - USD ($) $ in Millions			3 Months Ended
		Jan. 04, 2024	Mar. 31, 2024
Goodwill [Roll Forward]
Beginning balance	[1]		$ 120.7
Acquisitions - Allkem Livent Merger			1,189.2
Ending balance			1,309.9
Allkem
Goodwill [Roll Forward]
Beginning balance			0.0
Acquisitions - Allkem Livent Merger		$ 1,189.2
Ending balance			1,189.2
Nemaska Lithium
Goodwill [Roll Forward]
Beginning balance			120.7
Acquisitions - Allkem Livent Merger		$ 0.0
Ending balance			$ 120.7
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Revenue Recognition - Disaggregation of Revenue by Major Geographical Region (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Consolidated Revenue	$ 261.2	$ 253.5	[1]
North America
Disaggregation of Revenue [Line Items]
Consolidated Revenue	20.7	51.9
Latin America
Disaggregation of Revenue [Line Items]
Consolidated Revenue	0.8	1.8
Europe, Middle East & Africa
Disaggregation of Revenue [Line Items]
Consolidated Revenue	19.6	32.8
Asia Pacific
Disaggregation of Revenue [Line Items]
Consolidated Revenue	220.1	167.0
China
Disaggregation of Revenue [Line Items]
Consolidated Revenue	125.9	88.4
Japan
Disaggregation of Revenue [Line Items]
Consolidated Revenue	46.0	35.1
United States
Disaggregation of Revenue [Line Items]
Consolidated Revenue		50.2
South Korea
Disaggregation of Revenue [Line Items]
Consolidated Revenue	$ 45.5	$ 33.4
[1] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem.

v3.24.1.1.u2

Revenue Recognition - Narrative (Details) - Revenue from Contract with Customer Benchmark - Customer Concentration Risk	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Customer One
Disaggregation of Revenue [Line Items]
Concentration risk percentage	22.00%	25.00%
Customer Two
Disaggregation of Revenue [Line Items]
Concentration risk percentage	16.00%	19.00%
Ten Largest Customers
Disaggregation of Revenue [Line Items]
Concentration risk percentage	79.00%	68.00%
Customer Three
Disaggregation of Revenue [Line Items]
Concentration risk percentage	14.00%

v3.24.1.1.u2

Revenue Recognition - Disaggregation of Revenue By Major Product Category (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Consolidated Revenue	$ 261.2	$ 253.5	[1]
Lithium Hydroxide
Disaggregation of Revenue [Line Items]
Consolidated Revenue	110.6	152.7
Lithium Carbonate
Disaggregation of Revenue [Line Items]
Consolidated Revenue	79.8	9.5
Butyllithium and Other Lithium Specialties
Disaggregation of Revenue [Line Items]
Consolidated Revenue	46.0	91.3
Spodumene Concentrate
Disaggregation of Revenue [Line Items]
Consolidated Revenue	$ 24.8	$ 0.0
[1] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem.

v3.24.1.1.u2

Revenue Recognition - Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	[2]	Dec. 31, 2023	[1]
Revenue from Contract with Customer [Abstract]
Receivables from contracts with customers, net of allowances	$ 93.5			$ 106.7
Contract liability - short-term	30.6			4.4
Contract liability - long-term	218.3			$ 217.8
(Decrease)/increase receivables from contracts with customers, net of allowances	(13.2)
(Decrease)/increase contract liability - short-term	26.2	$ (13.0)
(Decrease)/increase contract liability - long-term	$ 0.5
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem. [2] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem.

v3.24.1.1.u2

Revenue Recognition - Performance Obligations (Details) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01 $ in Billions	Mar. 31, 2024 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation	$ 1.8
Expected timing of satisfaction of performance obligations	5 years

v3.24.1.1.u2

Inventories, Net - Schedule of Inventory (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Finished goods	$ 114.1	$ 59.1
Semi-finished goods	122.2	108.8
Raw materials, supplies, and other	92.5	49.6
Inventory, net	$ 328.8	$ 217.5	[1]
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Investments- Equity Method Investments (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Investments	$ 38.6	$ 34.8	[1]
ESM ILiAD, LLC
Schedule of Equity Method Investments [Line Items]
Investments	30.1	30.1
Arcadium NQSP
Schedule of Equity Method Investments [Line Items]
Investments	6.0	4.7
Other
Schedule of Equity Method Investments [Line Items]
Investments	$ 2.5	$ 0.0
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Investments- Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Schedule of Equity Method Investments [Line Items]
Investment carrying amount	$ 38.6	$ 34.8	[1]
Toyotsu Lithium Corporation
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage	75.00%
Subsidiary, economic interest percentage, noncontrolling interest	51.00%
Toyotsu Lithium Corporation | Class A Voting Shares
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage	49.00%
Toyotsu Lithium Corporation | Class B Nonvoting Shares
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage	100.00%
Toyota Tsusho Corporation
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage	49.00%
Subsidiary, economic interest percentage, noncontrolling interest	25.00%
Toyota Tsusho Corporation | Class A Voting Shares
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage	51.00%
ESM ILiAD, LLC
Schedule of Equity Method Investments [Line Items]
Investment carrying amount	$ 30.1	$ 30.1
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Partially-Owned Subsidiaries and Noncontrolling Interests (Details) - USD ($) $ in Millions		3 Months Ended
	Mar. 28, 2024	Mar. 31, 2024	Mar. 31, 2023		Mar. 27, 2024	Dec. 31, 2023		Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Equity in net loss of unconsolidated affiliate		$ 0.0	$ 8.1	[1],[2]
Cash and cash equivalents		472.7				$ 237.6	[3]
Long-term debt		583.3				302.0
Cash held in subsidiary entities		$ 89.5
Investment interest-free loan repaid dividends percentage		33.00%
Project Loan Facility - Stage 1 of Olaroz Plant | Line of Credit
Schedule of Equity Method Investments [Line Items]
Restricted cash, noncurrent		$ 24.6
Sales De Jujuy Pte Ltd
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage		72.68%
Sales De Jujuy Pte Ltd | Toyota Tsusho Corporation
Schedule of Equity Method Investments [Line Items]
Subsidiary, ownership percentage, noncontrolling owner		27.32%
Sales De Jujuy S.A
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage		66.50%
Sales De Jujuy S.A | Jujuy Energia y Minera Sociedad del Estado
Schedule of Equity Method Investments [Line Items]
Subsidiary, ownership percentage, noncontrolling owner		8.50%
Sales De Jujuy S.A | Sales De Jujuy Pte Ltd
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage		91.50%
Olaroz
Schedule of Equity Method Investments [Line Items]
Ownership interest by parent percentage		66.50%
Olaroz | Toyota Tsusho Corporation
Schedule of Equity Method Investments [Line Items]
Subsidiary, ownership percentage, noncontrolling owner		25.00%
Olaroz | Jujuy Energia y Minera Sociedad del Estado
Schedule of Equity Method Investments [Line Items]
Subsidiary, ownership percentage, noncontrolling owner		8.50%
Nemaska Lithium Inc.
Schedule of Equity Method Investments [Line Items]
Equity interest percentage								50.00%
Equity method investments								$ 437.1
Equity in net loss of unconsolidated affiliate			$ 8.1
Cash and cash equivalents						$ 43.0
Proceeds from investment cash in second advance payment	$ 150.0
Long-term debt					$ 97.8
Contract liabilities from customers					$ 52.2
Cumulative proceeds from supply agreement		$ 225.0
Nemaska Lithium Inc. | Scenario, Plan
Schedule of Equity Method Investments [Line Items]
Advances to contract manufacturers		350.0
Sales De Jujuy Pte Ltd
Schedule of Equity Method Investments [Line Items]
Accounts receivable, fair value		$ 5.5
[1] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem. [2] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem. [3] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Property, Plant and Equipment, Net (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Total cost	$ 7,072.8		$ 2,506.2
Accumulated depreciation	(279.1)		(269.1)
Property, plant and equipment, net	6,793.7		2,237.1	[1]
Depreciation	15.4	$ 6.1
Land and land improvements
Property, Plant and Equipment [Line Items]
Total cost	325.2		106.2
Buildings
Property, Plant and Equipment [Line Items]
Total cost	$ 724.5		134.9
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	20 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	40 years
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total cost	$ 791.6		420.7
Mineral rights
Property, Plant and Equipment [Line Items]
Total cost	3,278.0		560.0
Construction in progress
Property, Plant and Equipment [Line Items]
Total cost	$ 1,953.5		$ 1,284.4
Land improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	20 years
Leased plant and equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	1 year
Leased plant and equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years 6 months
Other machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Other machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	18 years
Software | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Software | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Restructuring and Other Charges - Restructuring Charges in Consolidated Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Restructuring charges:
Restructuring charges	$ 10.9	$ 1.7
Other charges:
Costs related to the Allkem Livent Merger	67.0	0.0
Other	5.7	0.2
Total Restructuring and other charges	$ 83.6	$ 1.9

v3.24.1.1.u2

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Income tax expense	$ 53.8	$ 23.9	[1]
Effective tax rate	73.00%	17.20%
[1] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem.

v3.24.1.1.u2

Asset Retirement Obligations (Details) - Allkem Livent Merger $ in Millions	Mar. 31, 2024 USD ($)
Mt Cattlin Spodumene Mine
Business Acquisition [Line Items]
Asset retirement obligations acquired	$ 7.3
Olaroz
Business Acquisition [Line Items]
Asset retirement obligations acquired	1.5
Galaxy Lithium (SAL DE VIDA) S.A
Business Acquisition [Line Items]
Asset retirement obligations acquired	$ 0.9

v3.24.1.1.u2

Debt - Long-term Debt (Details) - USD ($) $ in Millions	Mar. 28, 2024	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Transaction costs/discount		$ (2.0)	$ (2.4)
Subtotal long-term debt (including current maturities)		583.3	302.0
Less current maturities		(80.6)	(2.4)	[1]
Long-term debt		502.7	299.6	[1]
Total debt assumed in Allkem Livent Merger
Debt Instrument [Line Items]
Subtotal long-term debt (including current maturities)		$ 284.3	0.0
Nemaska Lithium | Prepayment Agreement
Debt Instrument [Line Items]
Convertible debt, interest rate		8.90%
Transaction costs/discount	$ (52.2)	$ (20.2)	(19.8)
Nemaska - Prepayment agreement/Other		75.0	75.0
Debt instrument advance received	$ 150.0
Nemaska Lithium | Other
Debt Instrument [Line Items]
Nemaska - Prepayment agreement/Other		$ 0.4	3.4
Line of Credit | Project Loan Facility - Stage 1 of Olaroz Plant
Debt Instrument [Line Items]
Convertible debt, interest rate		4.896%
Long-term debt, gross		$ 9.2	0.0
Line of Credit | Project Loan Facility - Stage 2 of Olaroz Plant
Debt Instrument [Line Items]
Convertible debt, interest rate		2.6119%
Long-term debt, gross		$ 144.0	0.0
Line of Credit | Project Financing Facility - Sal de Vida
Debt Instrument [Line Items]
Convertible debt, interest rate		10.051%
Long-term debt, gross		$ 47.0	0.0
Line of Credit | Affiliate Loans with TTC
Debt Instrument [Line Items]
Convertible debt, interest rate		11.331%
Long-term debt, gross		$ 81.6	0.0
Line of Credit | Affiliate Loan with TLP
Debt Instrument [Line Items]
Convertible debt, interest rate		10.34%
Long-term debt, gross		$ 2.5	0.0
Convertible Debt
Debt Instrument [Line Items]
Convertible debt, interest rate		4.125%
Long-term debt, gross		$ 245.8	245.8
Revolving Credit Facility
Debt Instrument [Line Items]
Letters of credit outstanding, amount		15.5	15.5
Line of credit, remaining borrowing capacity		484.5	484.5
Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Long-term debt, gross		$ 0.0	$ 0.0
SOFR borrowings | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Credit facility, interest rate		7.18%
Base rate borrowings | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Credit facility, interest rate		9.25%
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Debt - Narrative (Details) $ / shares in Units, $ in Millions		3 Months Ended			12 Months Ended
	Jan. 04, 2024 USD ($) $ / shares	Mar. 31, 2024 USD ($) day loan $ / shares	Mar. 31, 2023 USD ($)	[1],[2]	Dec. 31, 2020 USD ($) day $ / shares	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Loss on debt extinguishment		$ 0.2	$ 0.0
Convertible Debt
Debt Instrument [Line Items]
Debt interest rate		4.125%
Long-term debt, gross		$ 245.8				$ 245.8
Convertible Debt | Conversion Circumstance One
Debt Instrument [Line Items]
Initial conversion price per share (in dollars per share) | $ / shares		$ 4.72
Percentage of conversion price		130.00%
Trading days | day		20
Consecutive trading days | day		30
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt, gross		$ 0.0				0.0
2025 Notes
Debt Instrument [Line Items]
Debt discount, excluding amortization		$ 2.5
2025 Notes | Convertible Debt
Debt Instrument [Line Items]
Debt interest rate		4.125%			4.125%
Aggregate principal amount of debt					$ 245.8
Initial conversion price per share (in dollars per share) | $ / shares	$ 3.63				$ 8.73
Percentage of conversion price					130.00%
Trading days | day					20
Consecutive trading days | day					30
Redemption price, percentage of principal amount					100.00%
Business day period | day					5
Consecutive trading day period | day					5
Trading price as percentage of closing price of common stock					98.00%
Amortization of discount and transaction costs		$ 0.4
Conversion ratio (in shares)		0.275459331			0.1144885
Convertible Senior Notes, Over-Allotment Option | Convertible Debt
Debt Instrument [Line Items]
Proceeds from Offering					$ 238.2
Payments of debt issuance costs					$ 7.6
Credit Agreement | Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 500.0
Maximum increase in revolving credit commitments	$ 700.0
Floor rate	0.00%
Commitment fee percentage	0.25%
Deferred financing costs		$ 0.8
Loss on debt extinguishment		0.2
Deferred financing costs		$ 2.7
Net leverage ratio		3.5
Minimum interest coverage ratio		3.5
Credit Agreement | Line of Credit | Revolving Credit Facility | SOFR borrowings
Debt Instrument [Line Items]
Basis spread on variable rate	0.10%
Credit Agreement | Line of Credit | Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 50.0
Project Loan Facility - Stage 1 of Olaroz Plant | Line of Credit
Debt Instrument [Line Items]
Debt interest rate		4.896%
Aggregate principal amount of debt		$ 9.2
Percentage of debt hedged by interest rate		88.60%
Long-term debt, gross		$ 9.2				0.0
Restricted cash, noncurrent		$ 24.6
Project Loan Facility - Stage 1 of Olaroz Plant | Line of Credit | SOFR borrowings
Debt Instrument [Line Items]
Basis spread on variable rate		0.80%
Project Loan Facility for Stage 1 | Line of Credit
Debt Instrument [Line Items]
Debt instrument, percent securitized		82.35%
Project Loan Facility - Stage 2 of Olaroz Plant | Line of Credit
Debt Instrument [Line Items]
Debt interest rate		2.6119%
Long-term debt, gross		$ 144.0				0.0
Restricted cash, noncurrent		$ 24.6
Affiliate Loans with TTC | Line of Credit
Debt Instrument [Line Items]
Debt interest rate		11.331%
Aggregate principal amount of debt		$ 93.0
Long-term debt, gross		81.6				0.0
Restricted cash, noncurrent		$ 77.8
Number of loans | loan		11
Project Financing Facility - Sal de Vida | Line of Credit
Debt Instrument [Line Items]
Debt interest rate		10.051%
Maximum borrowing capacity		$ 180.0
Long-term debt, gross		47.0				$ 0.0
Restricted cash, noncurrent		$ 32.5
Project Financing Facility - Sal de Vida | Line of Credit | SOFR borrowings
Debt Instrument [Line Items]
Basis spread on variable rate		4.80%
Project Financing Facility - Sal de Vida | Line of Credit | Adjusted Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate		0.25%
[1] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem. [2] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem.

v3.24.1.1.u2

Share-based Compensation - Narrative (Details) $ / shares in Units, $ in Millions			3 Months Ended
	Jan. 04, 2024 shares	Dec. 22, 2023	Mar. 31, 2024 USD ($) publicly_traded_peer $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of publicly traded peers | publicly_traded_peer			10
Weighted average grant date fair value (in dollars per share) | $ / shares			$ 1.91
Legacy Livent Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)			6,579,305
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based payment award, expiration period (in years)			10 years
Unrecognized compensation cost related to unvested stock options | $			$ 5.5
Requisite service period (in years)			1 year 7 months 6 days
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $			$ 13.3
Requisite service period (in years)			1 year 8 months 12 days
Accelerated vesting, number (in shares)			927,510
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accelerated vesting, number (in shares)	96,885
Performance Shares | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		100.00%
Arcadium Lithium Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)			64,548,000
Share-based payment award, expiration period (in years)			10 years

v3.24.1.1.u2

Share-based Compensation - Stock Compensation (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense, tax	$ 0.8
Stock compensation expense	13.2
Selling, General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Gross stock compensation charges	2.3
Restructuring Charges
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Gross stock compensation charges	13.5
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense, tax	0.1
Stock compensation expense	0.4
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense, tax	0.7
Stock compensation expense	12.4
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense, tax	0.1
Stock compensation expense	$ 0.4

v3.24.1.1.u2

Share-based Compensation - Black Scholes Assumptions (Details) - Stock Option	3 Months Ended
	Mar. 31, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0.00%
Expected volatility	31.18%
Expected life (in years)	6 years
Risk-free interest rate	4.08%

v3.24.1.1.u2

Share-based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Number of Options Granted But Not Exercised
Beginning balance (in shares)	5,060,687
Granted (in shares)	2,517,175
Exercised (in shares)	(53,056)
Ending balance (in shares)	7,524,806	5,060,687
Exercisable (in shares)	4,142,996,000
Weighted-Average Remaining Contractual Life (in Years)
Outstanding	6 years 7 months 6 days	5 years 7 months 6 days
Exercisable	4 years 10 months 24 days
Weighted-Average Exercise Price Per Share
Outstanding (in dollars per share)	$ 6.73
Granted (in dollars per share)	4.95
Exercised (in dollars per share)	4.05
Outstanding (in dollars per share)	6.28	$ 6.73
Exercisable (in dollars per share)	$ 6.25
Aggregate Intrinsic Value (in Millions)
Outstanding	$ 0.8	$ 6.5
Exercised	0.0
Exercisable	$ 0.8

v3.24.1.1.u2

Share-based Compensation - RSU and PRSU Activity (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended
	Jan. 12, 2024	Jan. 03, 2024	Mar. 31, 2024	Dec. 31, 2023
RSU awards
Number of awards
Nonvested, beginning balance (in shares)			2,287,088
Granted (in shares)	1,080,825		2,238,079
Vested (in shares)		(768,440)	(1,816,439)
Nonvested, ending balance (in shares)			2,708,728
Weighted-Average Grant Date Fair Value
Nonvested, beginning balance (in dollars per share)			$ 7.83
Granted (in dollars per share)			5.99
Vested (in dollars per share)			7.11
Nonvested, ending balance (in dollars per share)			$ 6.83
Aggregate Intrinsic Value (in Millions)
Aggregate intrinsic value			$ 10.5	$ 17.1
Intrinsic value of awards vested		$ 5.3
Performance Shares
Number of awards
Nonvested, beginning balance (in shares)			96,885
Vested (in shares)			(96,885)
Nonvested, ending balance (in shares)			0
Weighted-Average Grant Date Fair Value
Nonvested, beginning balance (in dollars per share)			$ 9.43
Vested (in dollars per share)			9.43
Nonvested, ending balance (in dollars per share)			$ 0
Aggregate Intrinsic Value (in Millions)
Aggregate intrinsic value			$ 0.0	$ 0.7

v3.24.1.1.u2

Equity - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Jan. 04, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity [Abstract]
Common stock, shares authorized (in shares)	5,000,000,000		5,000,000,000	5,000,000,000
Common stock, par value (in dollars per share)	$ 1.00	$ 1.00	$ 1.00	$ 1.00	$ 1.00
Preferred stock, shares authorized (in shares)	125,000,000		125,000,000
Preferred stock, par value (in dollars per share)	$ 1.00		$ 1.00
Dividends paid	$ 0	$ 0

v3.24.1.1.u2

Equity - Summary of Common Stock Activity (Details)	3 Months Ended
	Mar. 31, 2024 shares	Jan. 04, 2024	Dec. 31, 2023	Mar. 31, 2023
Issued
Beginning balance (in share)	433,059,946
Arcadium share option awards (in shares)	2,517,175
Ending balance (in share)	1,075,070,500
Treasury
Beginning balance (in shares)	(263,669)
Ending balance (in shares)	(263,208)
Outstanding
Beginning balance, outstanding (in shares)	432,796,277
Ending balance, outstanding (in shares)	1,074,807,292
Exchange ratio				2.406
Allkem Livent Merger
Outstanding
Exchange ratio		2.406
Ordinary Shares, $1.00 Per Share Par Value | Allkem Livent Merger
Outstanding
Exchange ratio			2.406
Performance Share and Restricted Stock Units (RSUs), Accelerated Awards
Issued
PRSU and RSU awards accelerated - Allkem Livent Merger (in shares)	648,969
Arcadium RSU awards
Issued
PRSU and RSU awards accelerated - Allkem Livent Merger (in shares)	15,248
Ordinary Shares, $1.00 Per Share Par Value
Issued
Issued to Allkem shareholders - Allkem Livent Merger (in shares)	641,337,840
Livent Plan | Performance Share and Restricted Stock Units (RSUs
Outstanding
Share issued during period (in shares)	648,969
Livent Plan | Ordinary Shares, $1.00 Per Share Par Value
Outstanding
Share issued during period (in shares)	641,337,840
Arcadium
Treasury
Net sales of treasury (in shares)	461
Outstanding
Net sales of treasury shares - Arcadium NQSP (in shares)	461
Arcadium | Arcadium RSU awards
Outstanding
Share issued during period (in shares)	15,248
Arcadium | Arcadium share option awards
Issued
Arcadium share option awards (in shares)	8,497
Outstanding
Share issued during period (in shares)	8,497

v3.24.1.1.u2

Equity - Schedule of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	[1]	$ 1,784.2
Other comprehensive income (losses) before reclassifications		0.2
Ending balance		6,183.4
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(49.8)	$ (51.0)
Other comprehensive income (losses) before reclassifications		(20.0)	1.7
Ending balance		(69.8)	(49.3)
Foreign currency adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(49.8)	(51.0)
Other comprehensive income (losses) before reclassifications		(20.2)	1.5
Ending balance		(70.0)	(49.5)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		0.0	0.0
Other comprehensive income (losses) before reclassifications		0.2	0.2
Ending balance		$ 0.2	$ 0.2
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Earnings Per Share - EPS Calculation (Details) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) $ / shares shares	Mar. 31, 2023 USD ($) $ / shares shares
Numerator:
Net income | $	$ 19.9	$ 114.8	[1],[2],[3],[4]
Denominator:
Weighted average ordinary shares outstanding - basic (in shares)	1,053.4	432.0	[2]
Dilutive share equivalents from share-based plans (in shares)	1.0	3.6
Dilutive share equivalents from 2025 Notes (in shares)	67.7	67.7
Weighted average ordinary shares outstanding - diluted (in shares)	1,122.1	503.3	[2]
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share [Abstract]
Basic earnings per ordinary share (in dollars per share) | $ / shares	$ 0.01	$ 0.27	[2]
Earnings Per Share, Diluted [Abstract]
Diluted earnings per ordinary share (in dollars per share) | $ / shares	$ 0.01	$ 0.23	[2]
Exchange ratio		2.406
[1] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem. [2] For the three months ended March 31, 2023, basic and diluted earnings per ordinary share and weighted average ordinary shares outstanding - basic and diluted amounts represent predecessor Livent and have been adjusted to reflect the 2.406 Exchange Ratio. Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 which do not include the operations of Allkem. [3] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023 and as of December 31, 2023, which do not include the financial position or operations of Allkem. [4] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem.

v3.24.1.1.u2

Earnings Per Share - Narrative (Details) - $ / shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities, exercise price (in dollars per share)	$ 4.95
Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share
Total antidilutive weighted average share equivalents (in shares)	3,683,694	438,154
Antidilutive securities, exercise price (in dollars per share)	$ 7.87	$ 9.70

v3.24.1.1.u2

Financial Instruments, Risk Management and Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Estimate of Fair Value Measurement
Derivative [Line Items]
Long-term debt value	$ 688.9
Long-term debt	583.3	$ 302.0
Open foreign currency forward contracts designated as cash flow hedges, U.S. dollar equivalent	32.3
Forward Contracts
Derivative [Line Items]
AOCI, net	0.2
Foreign Exchange Contract | Not Designated as Hedging Instrument
Derivative [Line Items]
Open foreign currency forward contracts designated as cash flow hedges, U.S. dollar equivalent	$ 87.1

v3.24.1.1.u2

Financial Instruments, Risk Management and Fair Value Measurements - Schedule of Fair Value of Derivative Instruments (Details) $ in Millions	Mar. 31, 2024 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total derivative assets	$ 0.2
Net derivative assets	0.2
Foreign Exchange contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total derivative assets	$ 0.2

v3.24.1.1.u2

Financial Instruments, Risk Management and Fair Value Measurements - Derivatives in Cash Flow Hedging Relationships (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	[1]	$ 1,784.2
Unrealized hedging gains, net of tax		0.2
Other comprehensive (loss)/income, net of tax		(20.0)	$ 1.7	[2]
Ending balance		6,183.4
Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		0.0	0.0
Unrealized hedging gains, net of tax		0.2	0.2
Other comprehensive (loss)/income, net of tax		0.2	0.2
Ending balance		$ 0.2	$ 0.2
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem. [2] Represents the results of predecessor Livent’s operations for three months ended March 31, 2023, which do not include the operations of Allkem.

v3.24.1.1.u2

Financial Instruments, Risk Management and Fair Value Measurements - Derivatives Not Designated As Cash Flow Hedging Instruments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative [Line Items]
Amount of pre-tax gain or (loss) recognized in income on derivatives	$ 10.6	$ 2.1
Foreign Exchange contracts | Other gain
Derivative [Line Items]
Amount of pre-tax gain or (loss) recognized in income on derivatives	13.9	0.0
Foreign Exchange contracts | Cost of sales
Derivative [Line Items]
Amount of pre-tax gain or (loss) recognized in income on derivatives	$ (3.3)	$ 2.1

v3.24.1.1.u2

Financial Instruments, Risk Management and Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Assets
Investments in deferred compensation plan	$ 6.0		$ 4.1
JEMSE Receivable	5.5
Equity securities	2.5
Derivatives – Foreign exchange	0.2
Total Assets	14.2		4.1
Liabilities
Deferred compensation plan obligation	7.2		6.7
Total Liabilities	7.2		6.7
Selling, General and Administrative Expenses
Liabilities
Mark-to-market gains (loss) on deferred compensation plan	0.8	$ (0.2)
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Investments in deferred compensation plan	6.0		4.1
JEMSE Receivable	0.0
Equity securities	2.5
Derivatives – Foreign exchange	0.0
Total Assets	8.5		4.1
Liabilities
Deferred compensation plan obligation	7.2		6.7
Total Liabilities	7.2		6.7
Significant Other Observable Inputs (Level 2)
Assets
Investments in deferred compensation plan	0.0		0.0
JEMSE Receivable	0.0
Equity securities	0.0
Total Assets	0.2		0.0
Liabilities
Deferred compensation plan obligation	0.0		0.0
Total Liabilities	0.0		0.0
Significant Unobservable Inputs (Level 3)
Assets
Investments in deferred compensation plan	0.0		0.0
JEMSE Receivable	5.5
Equity securities	0.0
Derivatives – Foreign exchange	0.0
Total Assets	5.5		0.0
Liabilities
Deferred compensation plan obligation	0.0		0.0
Total Liabilities	$ 0.0		$ 0.0

v3.24.1.1.u2

Commitments and Contingencies - Narrative (Details) $ in Millions	Mar. 31, 2024 USD ($)	Jan. 04, 2024 USD ($)	Oct. 31, 2023	Oct. 26, 2023	Feb. 28, 2023	Feb. 08, 2023
Lessor, Lease, Description [Line Items]
Export rate, percent of FOB value				1.50%	4.00%
Export LA Puna rate, percent of FOB value						0.025
Remaining export rate, percent of FOB value			0.015			0.015
Export rebate receivable	$ 4.5
Operating lease, weighted average remaining lease term (in years)	7 years 10 months 24 days
Operating lease, weighted average discount rate (as a percent)	8.40%
Allkem Livent Merger
Lessor, Lease, Description [Line Items]
Right of use assets - operating leases, net		$ 53.4
Operating lease liabilities - long-term		$ 53.4
Minimum
Lessor, Lease, Description [Line Items]
Lessee, operating lease, remaining lease term	2 years
Maximum
Lessor, Lease, Description [Line Items]
Lessee, operating lease, remaining lease term	27 years

v3.24.1.1.u2

Commitments and Contingencies - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Lease Cost
Operating lease cost	$ 4.3	$ 0.3
Short-term lease cost	0.1	0.1
Total lease cost	4.4	0.4
Cash paid for amounts included in the measurement of lease liabilities:
Cash paid for operating leases	$ 4.4	$ 0.3

v3.24.1.1.u2

Commitments and Contingencies - Maturity Analysis of Operating Lease Liabilities (Details) $ in Millions	Mar. 31, 2024 USD ($)
Undiscounted cash flows
Remainder of 2024	$ 11.9
2025	10.0
2026	9.1
2027	8.4
2028	8.0
Thereafter	31.0
Total future minimum lease payments	78.4
Less: Imputed interest	(23.3)
Total	$ 55.1

v3.24.1.1.u2

Supplemental Information - Prepaid and Other Current Assets (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Prepaid and other current assets
Tax related items	$ 71.8	$ 29.5
Prepaid expenses	30.8	16.9
Argentina government receivable	9.8	7.9
Other receivables	47.6	28.2
Bank Acceptance Drafts	0.6	0.0
Derivative assets (Note 17)	0.2	0.0
Other current assets	4.9	3.9
Total	$ 165.7	$ 86.4	[1]
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Supplemental Information - Other Assets (Details) - USD ($) $ in Millions	1 Months Ended
	Jun. 30, 2023	Mar. 31, 2024	Dec. 31, 2023		Nov. 06, 2023
Other assets
Argentina government receivable		$ 80.4	$ 71.3
Advance to contract manufacturers		26.8	27.6
Long-term semi-finished goods inventory		192.2	1.0
Tax related items		4.2	4.0
Capitalized software, net		1.7	1.1
Investment in transit - Nemaska Lithium		39.1	0.0
Other assets		97.7	22.7
Total		442.1	127.7	[1]
Condensed Balance Sheet Statements, Captions [Line Items]
Export tax receivable portion		34.8
Payment of deposit to customs authorities	$ 21.7
Argentina Government
Condensed Balance Sheet Statements, Captions [Line Items]
Export tax and export rebate receivable		$ 39.4	$ 38.8
Settlement amount to be paid					$ 34.3
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Supplemental Information - Accrued and Other Current Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Accrued and other current liabilities
Accrued payroll	$ 32.4	$ 31.2
Retirement liability - 401k	5.0	3.2
Environmental reserves, current	2.6	0.5
Severance	5.6	1.7
Accrued investment in unconsolidated affiliates	0.0	27.0
Other accrued and other current liabilities	81.0	73.2
Accrued and other liabilities	$ 126.6	$ 136.8	[1]
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

v3.24.1.1.u2

Supplemental Information - Other Long-Term Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Other long-term liabilities
Deferred compensation plan obligation	$ 7.2	$ 6.7
Contingencies related to uncertain tax positions	15.8	6.2
Self-insurance reserves	1.1	1.1
Asset retirement obligations	12.5	3.7
Other long-term liabilities	56.6	3.6
Total	93.2	$ 21.3	[1]
TMA Agreement, Uncertain Tax Positions
Other long-term liabilities
Contingencies related to uncertain tax positions	15.4
TMA Agreement, Indemnification Liability
Other long-term liabilities
Contingencies related to uncertain tax positions	$ 0.4
[1] Represents the financial position of predecessor Livent as of December 31, 2023, which does not include the financial position of Allkem.

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