Therap software company is trying to establish its optimal capital structure. The companys current capital structure consists of 35% debt and 65% equity; however, the treasurer believes that the firm should use more debt. Currently, the companys cost of equity capital is 9%, which is determined by CAPM. What would be Theraps estimated cost of equity capital if they change their capital structure to 50% debt? Risk-free rate is 3%, market index returns 11%, and the Theraps tax rate is 25%.