Pfd Company has debt with a yield to maturity of 6.7%, a cost of equity of 15.2%, and a cost of preferred stock of 9.4%. The market values of its debt, preferred stock, and equity are $9.8 million, $3.3 million, and $15.5 million, respectively, and its tax rate is 21%.

What is this firm's after-tax WACC?

Note: Assume that the firm will always be able to utilize its full interest tax shield.