Seven Myths of Market Definition

Abstract

Roughly a year into control of the federal antitrust agencies, President Biden’s antitrust team is turning its attention to policies and enforcement practices. They seem poised to start, as antitrust so often does, with market definition. This is an appropriate target for review but also perilous territory for the administration. Even slight missteps in market definition could spell disaster for broader enforcement objectives. To help policy work start from a solid foundation, this essay identifies seven common myths of market definition and explains how to avoid them.

Keywords: antitrust, market definition, merger guidelines

JEL Classification: K21, L41, L11