Since unsystematic risk can be eliminated simply by holding large portfolios, investors are not compensated for bearing unsystematic risk. Investors holding diversified portfolios are exposed only to systematic, market-related risks. Therefore, the relevant risk in the market’s risk/expected return trade-off is systematic risk, not total risk. The investor is rewarded with a higher expected return for bearing systematic, market-related risks. Only systematic risk is relevant in determining the premiums for bearing risk. Thus, the model predicts that a security’s return is related to that portion of risk that cannot be eliminated by portfolio combination.