问一道题：NO.PZ2018101501000061

问题如下：

Matt, CFA, is investigating the capital structure of Company M, a manufacturer of automobile. The company is in the 25% tax bracket. Matt expects that a change in financial leverage may result in different WACC. He has estimated different situations in the following table. Under which of the following situations, Company M`s WACC is smallest?

选项：

E/A = 75%

E/A = 70%

E/A = 60%

解释：

B is correct.

考点：Capital Structure Theory: with tax

解析：根据公式$WACC=\frac DA\ast r_d\ast(1-T)+\frac EA\ast r_e$

当D/A = 25%, E/A = 75%，代入得WACC = 0.25 * 7% * (1-25%) + 0.75 * 10% = 8.8125%

当D/A = 30%, E/A = 70%，代入得WACC = 0.3 * 7.2% * (1-25%) + 0.7 * 10.25% = 8.795%

当D/A = 40%, E/A = 60%，代入得WACC = 0.4 * 8.5% * (1-25%) + 0.6 * 11.5% = 9.45%