请教ROE,ROA关系式

不知道你的式子是哪里来的，正确的式子应该是ROE=(1-Tax rate)[ROA+(ROA-Interest rate)(Debt/Equity)]，这个式子可以转换成杜邦分析式。括号内整理得：ROE=(1-Tax rate)[ROA(1+(Debt/Equity))-Interest rate*(Debt/Equity)]=(1-Tax rate)[ROA(1+(Debt/Equity))*(1-(Interest rate*Debt)/EBIT)]，其中1-(Interest rate*Debt)/EBIT)是Pretax profit/EBIT，1-Tax rate是Net Profit/Pretax Profit，1+(Debt/Equity)是Assets/Equity，ROA是(EBIT/Sales)*(Sales/Assets)。ROE和ROA的分子是EBIT，分母分别是Equity和Assets。

推导很简单啦，ROE=Earnings to Equity,ROA=Earnings to Total Assets(=Total Debt + Total Equity), ROE=Earnings / (Total Assets - Total Debt)= Earnings / Total Assets * (Total Assets - Total Debt + Total Debt) / (Total Assets - Total Debt) = ROA*(1- Total Debt/(A-D))=……=ROA+D/E(ROA-I*(1-T))。需要注意的是，标准教科书式的ROA = EBIT / Total Assets，如果上面推导不出来，把ROA换成标准式走一遍。