The Noles Corporation finds that it is necessary to determine its marginal cost of capital. Nole's current capital structure calls for 40 percent debt, 15 percent preferred stock, and 45 percent common equity. Initially common equity will be in the form of retained earnings (Ke) and then new common stock (Kn). The costs of the various sources of financing are as follows:

Debt 5.6%

Preferred stock 9.0%

Retained earnings 12.0%

New common stock 13.2%

a. What is the initial weighted average cost of capital? (Include debt, preferred stock, and common equity in the form of retained earnings Ke.

b. If the firm has $12 million in retained earnings, at what size of investment will the firm run out of retained earnings?

c. What will the marginal cost of capital be immediately after that point? (Equity will remain at 45 percent of the capital structure, but will all be in the form of new common stock Kn.)

d. The 5.6 percent cost of debt referred to above applies only to the first $18 million of debt. After that the cost will be 7.2 percent. At what size of investment will there be a change in the cost of debt?

e. What will the marginal cost of capital be immediately after that point?

(Consider the facts in both parts c and d.)