Pfd Company has debt with a yield to maturity of 7.1% , a cost of equity of 12.8% , and a cost of preferred stock of 9.4% . The market values of its debt, preferred stock, and equity are 11.1 million, 3.4 million, and 16.4 million, respectively, and its tax rate is 22% . What is this firm's after-tax WACC? Note: Assume that the firm will always be able to utilize its full interest tax shield.