The Capital Asset Pricing Model (CAPM) is a financial model that establishes a linear relationship between the expected return of an asset and its systematic risk, often measured by beta. Developed by William Sharpe, John Lintner, and Jan Mossin in the 1960s, CAPM is widely used in finance for estimating the expected return on an investment and determining its appropriate level of risk.

The CAPM formula is as follows:

Expected Return (CAPM)=Risk-Free Rate+*β*×(Market Return−Risk-Free Rate)

Here are the key components of the CAPM formula:

**Expected Return (CAPM):**The expected return on an investment, often expressed as a percentage.**Risk-Free Rate:**The theoretical return on an investment with zero risk, typically approximated using the yield on government bonds.**Beta (**A measure of the asset’s systematic risk, indicating how much the asset’s returns are expected to move in relation to the overall market. A beta of 1 implies the asset moves in line with the market, a beta greater than 1 indicates higher volatility, and a beta less than 1 suggests lower volatility.*β*):**Market Return:**The expected return of the overall market, often represented by a broad market index like the S&P 500.

Key points about CAPM:

**Systematic Risk:**CAPM focuses on systematic risk, which is the risk that cannot be diversified away. It is the risk associated with the overall market movements.**Assumptions:**CAPM is based on several assumptions, including the assumption that investors are rational and risk-averse, markets are efficient, and there is a risk-free rate.**Market Portfolio:**CAPM assumes that all investors hold a combination of the risk-free asset and a risky portfolio called the market portfolio. The market portfolio contains all risky assets in the market, weighted by their market values.**Security Market Line (SML):**CAPM is often represented graphically by the Security Market Line, which shows the expected return for a given level of systematic risk (beta). Assets that lie above the SML are considered undervalued, while those below are overvalued.**Criticism:**CAPM has faced criticism, including concerns about its assumptions, the validity of using historical data to estimate future expected returns, and the one-factor model nature of beta.

Despite its criticisms, CAPM remains widely used in finance for its simplicity and as a benchmark for determining expected returns. However, many practitioners also recognize its limitations and may use alternative models or incorporate additional factors in their investment decision-making processes.