Equilibrium Prices of the Market Portfolio in the CAPM with Incomplete Financial Markets

Abstract

In the Capital Asset Pricing Model, we consider how introducing new assets will affect the prices of the existing ones. We prove that introducing new assets into financial markets increases the relative price of the market portfolio with respect to the risk-free bond if the elasticity of the marginal rates of substitution of the mean for standard deviation with respect to the latter is greater than one for every consumer; the relative price of the market portfolio decreases if the elasticity is less than one; and the relative price is left unchanged if the elasticity is equal to one.