Valuation theory says that expected stock returns are related to three variables: the book-to-market equity ratio (Bt/Mt), expected profitability, and expected investment. Given Bt/Mt and expected profitability, higher expected rates of investment imply lower expected returns. But controlling for the other two variables, more profitable firms have higher expected returns, as do firms with higher Bt/Mt. These predictions are confirmed in our tests.

We examine (1) how value premiums vary with firm size, (2) whether the CAPM explains value premiums, and (3) whether, in general, average returns compensate β in the way predicted by the CAPM. Loughran's (1997) evidence for a weak value premium among large firms is special to 1963 to 1995, U.S. stocks, and the book‐to‐market value‐growth indicator. Ang and Chen's (2005) evidence that the CAPM can explain U.S. value premiums is special to 1926 to 1963. The CAPM's more general problem is that variation in β unrelated to size and the value‐growth characteristic goes unrewarded throughout 1926 to 2004.