NO.PZ2022090805000015
问题如下：
A firm’s after-tax costs of debt, preferred stock, and equity are 8.4%, 14%, and 16%, respectively. Assuming equal funding from each source and a marginal tax rate of 30%, the weighted average cost of capital (%) is closest to:
选项：
A.12.8%
9.6%
14.5%
解释：
A is correct.
WACC = wdrd(1 – t) + wprp + were
= (1/3)(0.084) + (1/3)(0.14) + (1/3)(0.16)
= 0.028 + 0.047 + 0.053
= 12.8%
注意：题干中给出的债务成本已经是税「后」的，相当于 rd(1-t) 等于 8.4%，所以题干给出的税率没用
这里re rd和rp为啥是1/3呢
