COST OF COMMON EQUITY. A firm's target capital structure is 40 percent debt and 60 percent common equity. Its bonds have a 12 percent coupon, paid semiannually, a current maturity of 20 years, and sell for $1,000. The firm's marginal tax rate is 20 percent. The firm's policy is to use a risk premium of 4 percentage points when using the bond-yield-plus-risk-premium approach to find the cost of retained earnings (note that retained earnings is internally generated equity). Calculate the firm's cost of common equity using this method.