Uniqueness of Equilibrium in the Classical Capital Asset Pricing Model

By Lars Tyge Nielsen

Journal of Financial and Quantitative Analysis 23, 3 (1988), 329--336

Abstract

General equilibrium in the classical two-period mean-variance capital asset pricing model is not unique. Corresponding to one single set of expectations, utility functions, and an initial wealth distribution, there may be several equilibria, and an asset may have different prices, expected rates of return, and betas in different equilibria. However, any equilibrium portfolio is sustained by a unique price system, and if investors have decreasing risk aversion, then any equilibrium allocation of the risky assets is sustained by a unique price system.