The historical returns data for the past three years for Company A's stock is 6.0%, 15%,15% and that of the market portfolio is 10%,10% and 16%. If the risk-free rate of return is 4%, what is the cost of equity capital (required rate of return of company A's common stock) using CAPM? The historical returns data for the past three years for Company A's stock is 6.0%, 15%,15% and that of the market portfolio is 10%,10% and 16%. If the risk-free rate of return is 4%, what is the cost of equity capital (required rate of return of company A's common stock) using CAPM