CAPM was put forward by economists william sharpe and John lintner in 1960s. Since then, CAPM has had an important impact on the financial sector. This model assumes that non-systematic risks can be dispersed through diversification, but only systematic risks can play a role. As far as specific securities are concerned, the related risk is not the total risk, but the systemic risk of individual securities. The formula of capital asset pricing model is:
Rj=Rf+(Rm-Rf)β ( 1. 1)
Rj is the rate of return of securities J, Rf is the rate of return of risk-free assets, Rm is the rate of return of market equilibrium portfolio, and β is the β coefficient of securities J. The greater β, the higher the system risk and the higher the required rate of return. On the contrary, the smaller β, the lower the required rate of return. The beta coefficient of a portfolio is the weighted average of the beta coefficient of a single security.
Through the above statement, we can analyze the investment preferences and risks of fund managers.