What Is the Cost of Equity?
The cost of equity is the rate of return a company's shareholders expect to earn as compensation for the risk of holding its stock. From the company's perspective it is a cost, because if the stock fails to deliver that return, investors will sell and the share price will fall.
Unlike the cost of debt, the cost of equity is not directly observable in any contract, so it must be estimated. The standard tool is the capital asset pricing model, which ties the required return to how risky the stock is relative to the overall market.
How It Works
Under CAPM, Cost of Equity = Risk-Free Rate + Beta x Equity Risk Premium. The risk-free rate is typically the yield on a long-term government bond, beta measures the stock's sensitivity to market moves, and the equity risk premium is the extra return investors historically demand for holding stocks over risk-free bonds.
The cost of equity is always higher than the cost of debt for the same company, because shareholders are paid last in a bankruptcy and their returns are not contractually guaranteed. Analysts sometimes add a size premium for small companies or a country risk premium for emerging markets.
Example
Suppose the 10-year Treasury yields 4%, a company's beta is 1.2, and the equity risk premium is 5.5%. The cost of equity is 4% + 1.2 x 5.5% = 4% + 6.6% = 10.6%. If the same company's after-tax cost of debt is 4.5%, equity holders are demanding more than double the lenders' return, reflecting their riskier position in the capital structure.
Why It Matters
The cost of equity feeds directly into WACC and therefore into every DCF valuation, and it is the discount rate used on its own in a dividend discount model or a levered DCF. It also sets the bar for corporate decisions: buybacks, dividends, and projects only make sense if they generate returns above what shareholders could earn elsewhere for similar risk.
A classic interview question asks why the cost of equity exceeds the cost of debt, testing whether you understand seniority, contractual claims, and risk.
