```\nFile: PrimeRateLib.sol\n        // This is purely done to fully reconcile off chain accounting with the edge condition where\n        // leveraged vaults lend at zero interest.\n        int256 fCashDebtInReserve = -int256(s.fCashDebtHeldInSettlementReserve);\n        int256 primeCashInReserve = int256(s.primeCashHeldInSettlementReserve);\n        if (fCashDebtInReserve > 0 || primeCashInReserve > 0) {\n            int256 settledPrimeCash = convertFromUnderlying(settlementRate, fCashDebtInReserve);\n            int256 excessCash;\n            if (primeCashInReserve > settledPrimeCash) {\n                excessCash = primeCashInReserve - settledPrimeCash;\n                BalanceHandler.incrementFeeToReserve(currencyId, excessCash);\n            } \n\n            Emitter.emitSettlefCashDebtInReserve(\n                currencyId, maturity, fCashDebtInReserve, settledPrimeCash, excessCash\n            );\n        }\n```\n