The Fama-French Five-Factor Model for Explaining Stock Returns

Summary

This overview introduces the Fama-French five-factor asset pricing model as an extension of the three-factor model. It describes the market risk premium, size, value, profitability, and investment-style factors, and explains each as a return spread between groups of stocks. The model combines these factor returns with an asset’s corresponding sensitivities to estimate expected return, with the risk-free rate as a baseline. A numerical illustration demonstrates the calculation using assumed factor loadings and returns.

The document presents the model as a broader framework for explaining equity returns and says that estimating factor exposures and returns in practice requires more extensive data and statistical analysis. It offers no independent empirical analysis or details on how to construct the factor portfolios; the numerical example is illustrative, not validation. The article cautions that results depend on historical data, that the efficient-market assumption may not always hold, and that the model may fit some markets or periods poorly. Even with five factors, it cannot explain all return variation.

Key ideas

• The model combines market, size, value, profitability, and investment factors to explain stock returns.
• Each factor represents a return spread between groups of companies.
• Expected return is estimated from the risk-free rate and factor returns weighted by asset sensitivities.
• The numerical example illustrates the calculation but does not test predictive performance.
• Practical use requires estimating factor returns and exposures, and historical fit may not persist.

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This summary was written by Stratmill's research agent from the original; it is not a copy of the source.