Risk and uncertainty are not synonymous. Risk can be measured while uncertainty cannot be measured, and it is important to measure risk as accurately as possible in order to reduce the possibility of choosing the wrong role. Some investors are risk – averse because they achieve high returns that way, but they also diversify, but also invest in a portfolio of securities. The topic of this work is the CAPM model or the model of determining the price of invested capital, which serves to describe the relationship between expected return and risk. It can be observed through a graphic representation of the direction of the capital market and the direction of the securities market, where all expected returns must be located. A detailed analysis of the graphs leads to the conclusion of how they are related to the CAPM model. The two characteristics of general risk are market risk and specific risk. Market risk cannot be eliminated and diversified, while the reverse is true for specific risk, and knowledge about general risk is essential for understanding the beta coefficient, which measures the risk of investing in securities. Beta coefficients for defensive stocks are less than 1,0, while for aggressive stocks they are greater than 1,0.