Common ownership, institutional investors, and welfare

Abstract

This study evaluates the effects of institutional investors' common ownership of firms competing in the same market. Overall, common ownership has two opposing effects: (a) it serves as a device for weakening market competition, and (b) it induces diversification, thereby reducing portfolio risk. We conduct a detailed welfare analysis within which the competition-softening effects of an increased degree of common ownership is weighted against the associated diversification benefits.