Oriole Co. has a capital structure, based on current market values, that consists of 37 percent debt, 15 percent preferred stock, and 48 percent common stock. If the returns required by investors are 10 percent, 13 percent, and 15 percent for the debt, preferred stock, and common stock, respectively, what is Oriole's after-tax WACC? Assume that the firm's marginal tax rate is 28 percent. (Do not round intermediate calculations. Round answer to 1 decimal place, e.g. 15.2\%.) After tax WACC %