Market definition remains a critical part of most antitrust cases, despite attempts to obviate it. While many commentators have argued that a particular policy change may theoretically broaden or narrow antitrust markets, and thereby affect substantive antitrust enforcement, none has empirically...

With the adoption of the 2020 Vertical Merger Guidelines, the U.S. antitrust agencies have updated their guidance on vertical mergers for the Twenty-First Century. Although economists have long recognized the procompetitive benefits most vertical mergers generate, the law has not always followed...