Exam CFA® Level 1 topic 1 question 2721 discussion

J. Ross and Sons Inc. has a target capital structure that calls for 40 percent debt, 10 percent preferred stock, and 50 percent common equity. The firm's current after-tax cost of debt is 6 percent, and it can sell as much debt as it wishes at this rate. The firm's preferred stock currently sells for $90 a share and pays a dividend of $10 per share; however, the firm will net only $80 per share from the sale of new preferred stock. Ross expects to retain $15,000 in earnings over the next year. Ross' common stock currently sells for $40 per share, but the firm will net only $34 per share from the sale of new common stock. The firm recently paid a dividend of $2 per share on its common stock, and investors expect the dividend to grow indefinitely at a constant rate of 10 percent per year. What is the firm's cost of retained earnings?