NO.PZ2016012101000128
问题如下:
Assuming no changes in other variables, which of the following would decrease ROA?
选项:
A.A decrease in the effective tax rate.
B.A decrease in interest expense.
C.An increase in average assets.
解释:
C is correct.
Assuming no changes in other variables, an increase in average assets (an increase in the denominator) would decrease ROA. A decrease in either the effective tax rate or interest expense, assuming no changes in other variables, would increase ROA.
解析:根据题目解释,这道题是根据ROA=NI/asset来计算的,更严谨的公式是ROA= [NI+int(1-t)]/asset,不管是哪个公式,C选项都能选出来,分母增加肯定会导致ROA变小。
如果用简化的公式,interest expense降低会增加分子NI,ROA变大,如果用分子是NI+int(1-t)的公式,NI中扣掉了利息费用,然后又加回来,一减一增抵消了利息费用,ROA不变,所以不管用哪个公式,B都不对。
effective tax rate变小,简化的公式,NI变大,ROA变高,严谨的公式分子也是变大的,所以A不对。
为什么interest expense降低会增加分子NI,ROA变大,不是降低分子NI呢?
又为什么如果用分子是NI+int(1-t)的公式,NI中扣掉了利息费用,然后又加回来,一减一增抵消了利息费用,ROA不变。