The document provides an introduction to the Capital Asset Pricing Model (CAPM) for calculating the cost of equity for publicly traded companies. It discusses key concepts such as the value of a company being equal to the value of its debt plus the value of its equity. It also covers the equity return rate being a function of the risk-free rate plus a risk premium related to the market return rate. The CAPM model sets the expected return on equity equal to the risk-free rate plus the product of the market risk premium and the stock's beta coefficient.