Recent empirical studies demonstrate the significant extent to which a small number of well-known institutional investors have taken on large ownership interests in the majority of large U.S. public companies, including large ownership interests in horizontal competitors. The response to these...

Has the antitrust arsenal run out of novel theories or weapons? Think again. Recent scholarship has come to challenge conventional wisdom with the latest target of antitrust imagination being institutional investors, including diversified index funds. New economic research suggests that common...

Minority shareholdings have been on the regulatory agenda of competition authorities for some time. Recent empirical studies, however, draw attention to a new, thought provoking theory of harm: common ownership by institutional investors holding small, parallel equity positions in several...

Ownership of publicly listed German companies has undergone significant changes in recent years. The aim of this report is to document these trends since 2007 and analyze the extent to which firms that compete in the same product market are owned by the same investors, which is known as common...

We analyze horizontal mergers when the acquirer holds a passive partial ownership stake (PPO) in the target firm prior to the merger. We show that a PPO reduces the minimal synergy level necessary to make a merger beneficial for consumers. It follows that an antitrust authority ignoring existing...

“Horizontal shareholding” occurs when one or more equity funds own shares of competitors operating in a concentrated product market. For example, the four largest mutual fund companies might be large shareholders of all the major United States air carriers. A growing body of empirical...

Something old and important is lost sight of in a case like Ohio v. American Express, the Supreme Court's recent adoption of "platform" or "two-sided market" theory in American antitrust, and in theoretical efforts like the one on which it is based. A rarely discussed idea built in to American...

In dozens of cases each year alleging horizontal price fixing and other per se violations of Section 1 of the Sherman Act, the central issue is whether the defendants ever formed an agreement. One source of uncertainty in resolving this issue in litigation is the meaning of “tacit...

A bundled discount occurs when a seller charges less for a bundle of goods than for its components when sold separately. A characteristic of such discounting is that a rival who makes only one of the products in the bundle may have to give a larger per item discount in order to compensate the...

Empirical evidence that horizontal shareholding has created anticompetitive effects in airline and banking markets have produced calls for antitrust enforcement. In response, others have critiqued the airline and banking studies and argued that antitrust law cannot tackle any anticompetitive...