Market Power in Antitrust Cases

With many antitrust prohibitions, the existence of a violation depends upon whether the defendant possesses sufficient market power. In this Article, Professors Landes and Posner present an economic analysis of market power that provides the necessary foundation for application to particular cases and for formulation of antitrust policy. They use their approach to illuminate the perplexing issues of product and geographical market definition, the measurement of market power arising from mergers and within regulated industries, and the quantification of damages in monopolization and price-fixing cases. Finally, they argue that, despite the novelty of their formulation, it is compatible with the dominant judicial approach to these issues.