CAPM and market risk premiums
Use the risk-free rate, market premium and beta to estimate required return; check assumptions and risk before using it as a .
Explore market sensitivity and required return
Risk-free rate plus beta times market premium; same-period return %
What did you just see?
Beta measures market sensitivity rather than total volatility. Diversification reduces asset-specific risk but does not eliminate common market risk.
Interpret a negative premium
A market-return assumption below the risk-free rate gives a negative premium. The formula remains defined, but the horizon and forward-looking assumptions merit review.
Another example
- Match the currency and horizon of risk-free and market rates.
- Market premium is 9% − 3% = 6%.
- Required return is 3% + 1.2 × 6% = 10.2%.
Show formal definition and formula
CAPM relates an asset's systematic risk linearly to its equilibrium required return.
- Ri
- CAPM required return, not a guaranteed return.
- Rf
- Risk-free rate, using the same period as market return.
- Rm
- Market portfolio return.
- β
- Sensitivity to market returns, not total risk.
Common mistakes
Do not treat a historical market average as a certain future return, or assume high beta delivers higher returns in every period.
Frequently asked questions
Can beta be negative?
Yes. Negative beta indicates inverse co-movement with the chosen market; a positive premium can then imply a required return below the risk-free rate.
What are the limitations?
CAPM assumes diversified investors, common expectations, and idealized trading conditions. Beta, risk-free asset, and market-proxy choices affect the result, and the model does not capture every risk.
You can now explore…
- Connect the market premium to required return
- Understand beta and CAPM assumptions
Term reference1 terms
Open a term when you need a reminder. Underlined words in the article work too.