Spark PSM
Last updated
Last updated
The Spark PSM extends the Sky PSM liquidity on Ethereum mainnet to other chains, starting with Base. It allows swaps between USDS, sUSDS, and USDC with no slippage or fees beyond gas, making it the top liquidity source for these pairs in DeFi. This enables holders of USDC on supported networks to easily acquire sUSDS to earn yield, at no cost beyond gas.
Contract Name: PSM3.sol
Contract Source: Spark PSM code repository
| Network | Spark PSM Address |
|---|---|
usdc: IERC20 interface of USDC.
usds: IERC20 interface of USDS.
susds: IERC20 interface of sUSDS. Note that this is an ERC20 and not a ERC4626 because it's not on mainnet.
pocket: Address that holds custody of USDC. The pocket can deploy USDC to yield-bearing strategies. Defaulted to the address of the PSM itself.
rateProvider: Contract that returns a conversion rate between and sUSDS and USD in 1e27 precision.
totalShares: Total shares in the PSM. Shares represent the ownership of the underlying assets in the PSM.
shares: Mapping of user addresses to their shares.
setPocket: Sets the pocket address. Only the owner can call this function. This is a very important and sensitive action because it transfers the entire balance of USDC to the new pocket address. OZ Ownable is used for this function, and owner will always be set to the governance proxy.
swapExactIn: Allows swapping of assets based on current conversion rates, specifying an amountIn of the asset to swap. Ensures the derived output amount is above the minAmountOut specified by the user before executing the transfer and emitting the swap event. Includes a referral code.
swapExactOut: Allows swapping of assets based on current conversion rates, specifying an amountOut of the asset to receive from the swap. Ensures the derived input amount is below the maxAmountIn specified by the user before executing the transfer and emitting the swap event. Includes a referral code.
deposit: Deposits assets into the PSM, minting new shares. Includes a referral code.
withdraw: Withdraws assets from the PSM by burning shares. Ensures the user has sufficient shares for the withdrawal and adjusts the total shares accordingly. Includes a referral code.
previewDeposit: Estimates the number of shares minted for a given deposit amount.
previewWithdraw: Estimates the number of shares burned and the amount of assets withdrawn for a specified amount.
previewSwapExactIn: Estimates the amount of assetOut received for a given amount of assetIn in a swap.
previewSwapExactOut: Estimates the amount of assetIn required to receive a given amount of assetOut in a swap.
NOTE: These functions do not round in the same way as preview functions, so they are meant to be used for general quoting purposes.
convertToAssets: Converts shares to the equivalent amount of a specified asset.
convertToAssetValue: Converts shares to their equivalent value in USD terms with 18 decimal precision.
convertToShares: Converts asset values to shares based on the current exchange rate.
totalAssets: Returns the total value of all assets held by the PSM denominated in USD with 18 decimal precision.
Swap: Emitted on asset swaps.
Deposit: Emitted on asset deposits.
Withdraw: Emitted on asset withdrawals.
You can fetch the liquidity of the PSM3 by checking the USDS and sUSDS ERC20 token balances deposited in the PSM3 contract. USDC liquidity is being kept in the pocket address, but currently this address is set to the PSM3 contract itself, however it could be different in the future.
USDS and USDC are always converted at a fixed 1:1 ratio.
sUSDS is a yield accumulating token, meaning its price will increase vs USDS/USDC over time. A rate provider oracle is used to provide the sUSDS price.
Base