This handbook chapter appears in Antitrust Law & Economics (Keith Hylton, ed. 2010). It describes the role of market concentration in the legal framework for the antitrust review of horizontal mergers and evaluates the extent to which modern economic analysis supports a role for concentration in...

When the 1968 Merger Guidelines were drafted, both the economics and antitrust literatures addressed how competition could be softened when oligopolists anticipated the natural and predictable responses of their rivals to their competitive moves, such as price cuts or output expansion. But when...

This article takes a fresh look at a longstanding issue in antitrust economics and policy: the problem of oligopoly coordination. First, it explains why coordinated conduct in oligopoly markets is a serious problem and an appropriate concern of antitrust enforcement. It shows that empirical...