Why Common Ownership Creates Antitrust Risks

The share of stocks beneficially owned by institutional investors has increased substantially over the last three decades. Together with a high and increasing level of concentration in the asset management industry, this trend implies that a small number of institutional investors now constitute the largest shareholders of most publicly traded firms in the U.S. and in other developed economies. When the same set of investors owns most firms, they are bound to own several firms in the same industry. Such overlapping ownership interests among competitors, or “common ownership,” may imply a reduction in firms' incentives to compete, compared to a situation in which competitors are controlled by separate sets of investors, and may thus create antitrust risks. Recent empirical research shows evidence for such anti-competitive effects of common ownership. These findings have since ignited a debate on the antitrust risk posed by institutional investors, its legal implications and potential solutions. This article first illustrates the extent of present-day common ownership and discusses the economic logic of why common ownership leads to reduced incentives to compete and may cause anti-competitive outcomes. We then review some of the empirical evidence to date, discuss critiques of the same and explain the conceptual problems inherent with all potential policy solutions. The legal debate around these findings is discussed by a fast-growing literature, including contributions by other authors in this issue