The theory of choice under conditions of certainty has been extended by Von Neumann and Morgenstern [8], Friedman and Savage [5], Marschak [13], and others to conditions involving risk by assuming that individuals maximize their expected utility. The application of this theory to portfolio selection, to efficiency criteria, and to the explanation of the well-known phenomenon of diversification of assets has been carried further by Markowitz [11 and 12], Tobin [17], Samuelson [15], Sharpe [16], and Lintner [10], and more recently by Hadar and Russell [5] and Hanoch and Levy [8].

Using the mean-variance model, Sharpe [5] and Lintner [4] have derived an equilibrium model for price determination under uncertainty. Jean [2] has tried to generalize this model so that other moments of the distribution will be taken into account. The purpose of this note is to show that unlike the Sharpe-Lintner model, Jean's results make no economic sense.