Mutual Fund Summary Prospectus (497k)

Vanguard Mid-Cap Growth Index Fund

Summary Prospectus

April 12, 2013

Investor Shares for Participants

Vanguard Mid-Cap Growth Index Fund Investor Shares (VMGIX)

The Fund’s statutory Prospectus and Statement of Additional Information dated

April 12, 2013, are incorporated into and made part of this Summary Prospectus

by reference.

Before you invest, you may want to review the Fund’s Prospectus, which

contains more information about the Fund and its risks. You can find

the Fund’s Prospectus and other information about the Fund online at

www.vanguard.com/prospectus . You can also get this information at no

cost by calling 800-523-1188 or by sending an e-mail request to

online@vanguard.com.

The Securities and Exchange Commission (SEC) has not approved or disapproved these securities or

passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Investment Objective

The Fund seeks to track the performance of a benchmark index that measures the investment return of mid-capitalization growth stocks.

Fees and Expenses

The following table describes the fees and expenses you may pay if you buy and hold Investor Shares of the Fund.


Shareholder Fees
(Fees paid directly from your investment)

Sales Charge (Load) Imposed on Purchases	None
Purchase Fee	None
Sales Charge (Load) Imposed on Reinvested Dividends	None
Redemption Fee	None

Annual Fund Operating Expenses

(Expenses that you pay each year as a percentage of the value of your investment)


Management Expenses	0.20%
12b-1 Distribution Fee	None
Other Expenses	0.04%
Total Annual Fund Operating Expenses	0.24%

Example

The following example is intended to help you compare the cost of investing in the Fund’s Investor Shares with the cost of investing in other mutual funds. It illustrates the hypothetical expenses that you would incur over various periods if you invest $10,000 in the Fund’s shares. This example assumes that the Shares provide a return of 5% a year and that total annual fund operating expenses remain as stated in the preceding table. The results apply whether or not you redeem your investment at the end of the given period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:


1 Year	3 Years	5 Years	10 Years
$25	$77	$135	$306

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in more taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the previous expense example, reduce the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 38%.

Primary Investment Strategies

The Fund employs an indexing investment approach designed to track the performance of the MSCI US Mid Cap Growth Index, a broadly diversified index of growth stocks of mid-size U.S. companies. The Fund attempts to replicate the target index by investing all, or substantially all, of its assets in the stocks that make up the Index, holding each stock in approximately the same proportion as its weighting in the Index.

Primary Risks

An investment in the Fund could lose money over short or even long periods. You should expect the Fund’s share price and total return to fluctuate within a wide range, like the fluctuations of the overall stock market. The Fund is subject to the following risks, which could affect the Fund’s performance:

• Stock market risk , which is the chance that stock prices overall will decline. Stock markets tend to move in cycles, with periods of rising prices and periods of falling prices. The Fund’s target index may, at times, become focused in stocks of a particular sector, category, or group of companies, which could cause the Fund to underperform the overall stock market.

• Investment style risk , which is the chance that returns from mid-capitalization growth stocks will trail returns from the overall stock market. Historically, mid-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently.

An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Annual Total Returns

The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund‘s Investor Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns compare with those of the Fund‘s target index, which has investment characteristics similar to those of the Fund. Keep in mind that the Fund’s past performance does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447.

Annual Total Returns — Vanguard Mid-Cap Growth Index Fund Investor Shares

During the periods shown in the bar chart, the highest return for a calendar quarter was 17.99% (quarter ended September 30, 2009), and the lowest return for a quarter was –27.33% (quarter ended December 31, 2008).


Average Annual Total Returns for Periods Ended December 31, 2012

			Since
			Inception
			(Aug. 24,
	1 Year	5 Years	2006)
Vanguard Mid-Cap Growth Index Fund Investor Shares	15.81%	1.61%	5.31%
MSCI US Mid Cap Growth Index
(reflects no deduction for fees or expenses)	16.03%	1.82%	5.49%

Investment Advisor

The Vanguard Group, Inc.

Portfolio Manager

Donald M. Butler, CFA, Principal of Vanguard. He has managed the Fund since 2013.

Tax Information

The Fund’s distributions will be reinvested in additional Fund shares and accumulate on a tax-deferred basis if you are investing through an employer-sponsored retirement or savings plan. You will not owe taxes on these distributions until you begin withdrawals from the plan. You should consult your plan administrator, your plan’s Summary Plan Description, or your tax advisor about the tax consequences of plan withdrawals.

Payments to Financial Intermediaries

The Fund and its investment advisor do not pay financial intermediaries for sales of Fund shares.

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Vanguard Mid-Cap Growth Index Fund Investor Shares—Fund Number 832

CFA ^® is a trademark owned by CFA Institute.

THIS FUND IS NOT SPONSORED, ENDORSED, SOLD OR PROMOTED BY MSCI INC. (“MSCI”), ANY OF ITS AFFILIATES, ANY OF ITS DIRECT OR INDIRECT INFORMATION PROVIDERS OR ANY OTHER THIRD PARTY INVOLVED IN, OR RELATED TO, COMPILING, COMPUTING OR CREATING ANY MSCI INDEX (COLLECTIVELY, THE “MSCI PARTIES”). THE MSCI INDEXES ARE THE EXCLUSIVE PROPERTY OF MSCI. MSCI AND THE MSCI INDEX NAMES ARE SERVICE MARK(S) OF MSCI OR ITS AFFILIATES AND HAVE BEEN LICENSED FOR USE FOR CERTAIN PURPOSES BY VANGUARD. NONE OF THE MSCI PARTIES MAKES ANY REPRESENTATION OR WARRANTY, EXPRESS OR IMPLIED, TO THE OWNERS OF THIS FUND OR ANY MEMBER OF THE PUBLIC REGARDING THE ADVISABILITY OF INVESTING IN FUNDS GENERALLY OR IN THIS FUND PARTICULARLY OR THE ABILITY OF ANY MSCI INDEX TO TRACK CORRESPONDING STOCK MARKET PERFORMANCE. MSCI OR ITS AFFILIATES ARE THE LICENSORS OF CERTAIN TRADEMARKS, SERVICE MARKS AND TRADE NAMES AND OF THE MSCI INDEXES WHICH ARE DETERMINED, COMPOSED AND CALCULATED BY MSCI WITHOUT REGARD TO THIS FUND OR THE ISSUER OR OWNER OF THIS FUND. NONE OF THE MSCI PARTIES HAS ANY OBLIGATION TO TAKE THE NEEDS OF THE ISSUERS OR OWNERS OF THIS FUND INTO CONSIDERATION IN DETERMINING, COMPOSING OR CALCULATING THE MSCI INDEXES. NONE OF THE MSCI PARTIES IS RESPONSIBLE FOR OR HAS PARTICIPATED IN THE DETERMINATION OF THE TIMING OF, PRICES AT, OR QUANTITIES OF THIS FUND TO BE ISSUED OR IN THE DETERMINATION OR CALCULATION OF THE CONSIDERATION INTO WHICH THIS FUND IS REDEEMABLE. NONE OF THE MSCI PARTIES HAS ANY OBLIGATION OR LIABILITY TO THE OWNERS OF THIS FUND IN CONNECTION WITH THE ADMINISTRATION, MARKETING OR OFFERING OF THIS FUND.

ALTHOUGH MSCI SHALL OBTAIN INFORMATION FOR INCLUSION IN OR FOR USE IN THE CALCULATION OF THE MSCI INDEXES FROM SOURCES WHICH MSCI CONSIDERS RELIABLE, NONE OF THE MSCI PARTIES WARRANTS OR GUARANTEES THE ORIGINALITY, ACCURACY AND/OR THE COMPLETENESS OF ANY MSCI INDEX OR ANY DATA INCLUDED THEREIN. NONE OF THE MSCI PARTIES MAKES ANY WARRANTY, EXPRESS OR IMPLIED, AS TO RESULTS TO BE OBTAINED BY LICENSEE, LICENSEE’S CUSTOMERS OR COUNTERPARTIES, ISSUERS OF THE FUNDS, OWNERS OF THE FUNDS, OR ANY OTHER PERSON OR ENTITY, FROM THE USE OF ANY MSCI INDEX OR ANY DATA INCLUDED THEREIN IN CONNECTION WITH THE RIGHTS LICENSED HEREUNDER OR FOR ANY OTHER USE. NONE OF THE MSCI PARTIES SHALL HAVE ANY LIABILITY FOR ANY ERRORS, OMISSIONS OR INTERRUPTIONS OF OR IN CONNECTION WITH ANY MSCI INDEX OR ANY DATA INCLUDED THEREIN. FURTHER, NONE OF THE MSCI PARTIES MAKES ANY EXPRESS OR IMPLIED WARRANTIES OF ANY KIND, AND THE MSCI PARTIES HEREBY EXPRESSLY DISCLAIM ALL WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, WITH RESPECT TO ANY MSCI INDEX AND ANY DATA INCLUDED THEREIN. WITHOUT LIMITING ANY OF THE FOREGOING, IN NO EVENT SHALL ANY OF THE MSCI PARTIES HAVE ANY LIABILITY FOR ANY DIRECT, INDIRECT, SPECIAL, PUNITIVE, CONSEQUENTIAL OR ANY OTHER DAMAGES (INCLUDING WITHOUT LIMITATION LOST PROFITS) EVEN IF NOTIFIED OF THE POSSIBILITY OF SUCH DAMAGES.

SPI 832 042013