All that being said, the residual income valuation approach is a viable and increasingly popular method of valuation and can be implemented rather easily by even novice investors. When used alongside the other popular valuation approaches, residual income valuation can give you a clearer estimate of what the true intrinsic value of a firm may be. (Don't be overwhelmed by the many valuation techniques out there - knowing a few characteristics about a company will help you pick the best one. See How To Choose The Best Stock Valuation Method.)
Residual income is calculated as net income less a charge for the cost of capital. The charge is known as the equity charge and is calculated as the value of equity capital multiplied by the cost of equity or the required rate of return on equity. Given the opportunity cost of equity, a company can have positive net income but negative residual income.