The WACC K. Bell Jewelers wishes to explore the effect on its cost of capital of the rate at which the company pays taxes. The firm wishes to maintain a capital structure of 35% debt, 15% preferred stock, and 50% common stock. The cost of financing with retained earnings is 17%, the cost of preferred stock financing is 11%, and the before-tax cost of debt financing is 7%. Calculate the weighted average cost of capital (WACC) given a tax rate of 21%