tToken & s/vToken
tTokens are tokens minted and burnt upon supply and withdraw of assets to an Themis market. They denote the amount of crypto assets supplied and the yield earned on those assets. The tTokens’ value is pegged to the value of the corresponding supplied asset at a 1:1 ratio and can be safely stored, transferred or traded. All yield collected by the tTokens' reserves are distributed to tToken holders directly by continuously increasing their wallet balance.
All standard EIP20 methods are implemented for tTokens, such as
balanceOfwill always return the most up to date balance of the user, which includes their principal balance + the yield generated by the principal balance.
The sToken and vToken are debt Tokens. In Themis LendingPool's interest rate algorithm, the s/vToken increases over time along with the tToken. tToken & s/vToken are both minted and burned 1:1. Burning s/vToken when the user repays the borrowed assets means that the borrower will pay in more Tokens, and when the user's tToken increases, the corresponding Token is taken out when withdrawing to the pool.
s/vToken cannot be transferred without permission, and their Balance is constantly changing in the wallet, with the amount changing each time it is settled.
- When a tToken is Minted to a user's wallet, its number grows over time. It's always 1:1 at the time of Withdraw.
- The number of tToken may not grow linearly, the number of tToken in the user's wallet will increase passively, but there may be short-term peaks. For example, if a user deposits 100DAI to get 100tDAI, the tDAI might be 103 at one time, or 102.5 at some later time, but not less than 100. The longer the tDAI is held, the closer the real interest rate is to the predicted rate. This is because the number of tTokens will be rebased after the s/vToken is burned.
M1's borrowings also mint s/vToken, which means that M1's borrowings generate more s/vToken, and as the number of s/vToken increases, the interest rate at which tToken is settled also increases. And M1's collateral is pledged in the tToken contract.
M1's borrowings are also over-collateralized, and the size of the borrowing value of any s/vToken will not exceed the size of the total collateral value of tToken
The increase of tToken & s/vToken is an equilibrium relationship, where the increasing s/vToken will require the borrower to repay the interest, while the increasing tToken will give the supplier the ability to take out more passive income.
Overcollateralization keeps the number of s/vToken from exceeding the number of tToken.
When a pool is out on loan by other collateral borrowing, it means:
- the value of the collateral in the tToken of the pool is much greater than the value of the s/vToken.
- other collaterals would have significant idle liquidity.
- the interest rates of the tToken & s/vToken of that pool will spike, forcing borrowers to repay or liquidate
Other users who borrow short a pool overcollateralize the liquidity of other pools.
tToken can be supplied as a token in either Balancer or Curve's LP pool
- Users can earn fees or liquidity rewards for providing tToken liquidity on third-party platforms.
- Some LPs can continue to be used as collateral in M1, which can temporarily unlock liquidity.