This is a survey of the economic principles that underlie antitrust law and how those principles relate to competition policy. We address four core subject areas: market power, collusion, mergers between competitors, and monopolization. In each area, we select the most relevant portions of...

In competition law, market power requirements are often articulated in terms of market shares. The use of market share thresholds, however, conflates two distinct questions: (1) How much market power exists in a given situation? (2) How much market power should the law require? As a consequence,...