=SUMIF($O$12:$AX$12,"<="&Portfolio!$I$766,'Mth Pos PnL'!O175:AX175)-SUMIF($O$12:$AX$12,"<="&EOMONTH(Portfolio!$I$766,-12),'Mth Pos PnL'!O175:AX175)
That is my current formula
All is says is that sum returns in columns O to AX (where the monthly returns are) if they are between two dates
Instead of a sum formula (which is not compounding the monhtly returns) - I want to use a product formula so that it does do the compounding