Brothers Software is trying to establish its optimal capital. Its current capital structure consists of 25% debt and 75% equity; however, the CEO believes that the firm should use more debt. The risk-free rate is 4%, the market risk premium is 5%, and the firms tax rate is 25%. Currently, Brothers cost of equity is 12%. What would be the firms estimated cost of equity if it changed its capital structure to 40% debt and 60% equity?