sDAI (Savings DAI) is a yield-bearing token issued by MakedDAO and Spark Protocol, representing a staked version of DAI, a decentralized stablecoin pegged to the USD. sDAI allows users to earn yield from the Dai Savings Rate (DSR), a feature of the Maker Protocol, by depositing DAI into an ERC-4626 vault. It offers a non-custodial, permissionless way to accrue yield. The DAI Savings Rate is funded by Sky's and Maker's revenue, which includes fees from crypto collateralized loans, investments into U.S. Treasury Bills and its liquidity provisioning into SparkLend and the Spark Liquidity Layer.