The stable long-run CAPM and the cross-section of expected returns

The capital-asset-pricing model (CAPM) is one of the most popular methods of financial market analysis. But, evidence of the poor empirical performance of the CAPM has accumulated in the literature. For example, based on their empirical results regarding the relation between market Beta and average return, Fama and French (1996) conclude that the CAPM is no longer a useful tool for empirical financial market analysis. Most empirical studies of the conventional CAPM take, however, neither the fat-tails of return data nor the price relationship between an asset of interest and the bench market portfolio into account. In the framework of a univariate Beta-model we consider a stable long-run CAPM taking account of the fat-tails of stock returns and the common stochastic trends between stock prices. Using the same data used by Fama and French (1996), the stable long-run CAPM demonstrates that Markowitz rule of the expected returns and variance of returns can (still)- without any use of firm specific variables- explain the variation of the cross-sectional average returns.