Mean-semivariance behavior: An alternative behavioral model

The most widely-used measure of an asset's risk, beta, stems from an equilibrium in which investors display mean-variance behavior. This behavioral criterion assumes that portfolio risk is measured by the variance (or standard deviation) of returns, which is a questionable measure of risk. The semivariance of returns is a more plausible measure of risk (as Markowitz himself admits) and is backed by theoretical, empirical, and practical considerations. It can also be used to implement an alternative behavioral criterion, mean-semivariance behavior, that is almost perfectly correlated to both expected utility and the utility of mean compound return.