Omega Corporation has 500 million shares outstanding, now trading at $4 per share. The firm has estimated the expected rate of return to shareholders at about 15 percent. It has also issued long-term bonds at an interest rate of 8 percent. It pays tax at a marginal rate of 25 percent. What is Omega's after-tax WACC? Assume that $1,600 million of long-term bonds have been issued.