FeeManager Manual Review Findings

FMR-01M: Incorrect Fee Discount Assumption

Description:

The fee discount that is meant to be applied by the FeeManager contract for discounted borrowers is 25%, however, a static value discount of 25 is performed which is equal to 0.25% and may not always yield a 25% discount as the comments indicate.

Example:

Copy
86function calcBorrowFeeOnDebt (address borrower, address debtToken, uint256 debt, address collateralToken) external view returns (uint256)
87{
88  // 25 = 0.25% in basis point; 1 - 0.25 = 0.75% -> 25% discount
89  uint256 fee = IStakingManager(_ADDRESSES.stakingManager()).isDiscountedBorrower(borrower) ? _fee.borrow - 25 : _fee.borrow;
90
91
92  return _calcPercentOf(IOracle(_ADDRESSES.oracle()).convert(debtToken, collateralToken, debt), fee);
93}

Recommendation:

We advise the proportionate discount methodology applied on deposits to be also applied on borrows to ensure a uniform discount structure.

Alleviation:

A proper percentage based discount is now applied in the codebase.