The Capital Asset Pricing Model (CAPM) is a financial model that helps investors determine the expected return of an asset, such as a stock or bond. It is based on the premise that investors require a higher return for taking on additional risk. The model helps investors understand the relationship between risk and return and can be used to make informed investment decisions.

The CAPM formula is used to calculate the expected return of an asset, which is the sum of the risk-free rate and the risk premium. The risk-free rate is the return an investor can expect to receive on a risk-free investment, such as a U.S. Treasury bond. The risk premium is the additional return an investor expects to receive for taking on additional risk.

The formula for the CAPM is:

Expected return = Risk-free rate + (Beta x Market risk premium)

Where Beta is a measure of the volatility of an asset compared to the overall market. A Beta of 1 means the asset is as volatile as the market, while a Beta greater than 1 means the asset is more volatile than the market, and a Beta less than 1 means the asset is less volatile than the market.

The CAPM helps investors understand how much additional return they can expect to receive for taking on additional risk. For example, if an asset has a Beta of 1.5, an investor can expect to receive 1.5 times the market risk premium for taking on additional risk.

The CAPM is a widely used tool in finance, but it has its limitations. It assumes that markets are efficient, that all investors have access to the same information, and that investors are rational. However, real-world markets may not always behave as the CAPM assumes, so it is important for investors to consider other factors when making investment decisions.

Despite its limitations, the CAPM remains a useful tool for understanding the relationship between risk and return and can be a valuable tool for investors looking to make informed investment decisions.