This document discusses the cost of capital and how to calculate it. It defines cost of capital as the rate of return a firm must earn on its investments to maintain its market value and attract funds. It then discusses how to calculate the costs of different sources of capital including long-term debt, preferred stock, common stock, and retained earnings. It explains how to calculate the weighted average cost of capital (WACC) and discusses weighting schemes. Finally, it discusses how to determine break points and calculate the weighted marginal cost of capital (WMCC), which can be used with the investment opportunities schedule to make financing decisions.