UNIDOLLAR is a Proof of Liquidity and Proof of Stake Ethereum based token. That means the supply was sent to Uniswap and provided with initial liquidity. The staking mechanism is built directly into the smart contract which rewards users for staking their UNIUSD. Each transfer of UNIUSD between Ethereum addresses initiates a 2% tax. This 2% tax is then distributed to stakers autonomously and the rewards are proportionate to the amount of tokens a user has staked.