Interest rate received for positive daily excess cash
If the settings also provide a RiskFreeRateSym then CashIntPct is added to the current daily interest rate as determined by today's value of the risk-free rate series. In this case, CashIntPct would typically be negative, e.g. -0.5 if your broker pays 0.5% less than the fed funds rate (with floor of zero).
If RiskFreeRateSym is provided but CashIntPct is not provided or is 0 then no interest is received. You must specify a non-zero value of CashIntPct to include interest on excess cash in your backtests.
If CashIntPct is provided when there is no RiskFreeRateSym then CashIntPct is simply a fixed annual interest rate.
Daily net interest received or paid is added to combined S.Equity and therefore becomes part of the total return of the backtest.
The stats series S.Interest can be used to graph or reference the cumulative net interest received or paid in the account.
See also MarginIntPct which specifies the rate charged for negative excess cash (margin loan).