Abstract: Institutional Portfolio Restrictions, Diverse Investor Opportunity Sets, and Securities Market Equilibrium

Extract

This paper utilizes a two-parameter model of segmented securities markets to develop equilibrium implications concerning the impact of statutory investment restrictions upon the market prices and allocation of risky securities. The distinguishing feature of the model is the existence of a subset of securities common to the opportunities of all investors and therefore said to “span” the investor population. These common opportunities are shown to permit intersubset security transactions which integrate the various market segments and lead to the following theorem and tendency concerning equilibrium prices and portfolios:

Theorem: In the absence of active barriers against short positions, the equilibrium expected return for any security spanning the investor population is an exact linear function of its contribution to total market risk, irrespective of the number of distinct investor segments that may exist.

Tendency: The economic characteristics of the equilibrium risky portfolio for any investor, irrespective of the market segment to which he or she may belong, will approximate the characteristics of the market portfolio of all risky assets in the economy in all relevant risk dimensions.