return that, if accrued annually, produces the same after-tax accumulation as the taxable portfolio ... ,00x rate=30%(Interest income is taxed as oridinary income)Pre-tax standard deviation of PF returns 0 ... .5(16%)+0.5(6%)=11%After-tax standard deviation of PF returns 0.5(16%)(1-0.2)+0.5(6%)(1-0.3)=8.5