HHI

In new research, Eric Dunaway, Ana Espinola-Arredondo, and Felix Munoz-Garcia examine the Herfindahl-Hirschman Index (HHI) as a tool for merger review and show where it diverges from the consumer-surplus and total-welfare standards. In particular, the HHI fails to account for potential efficiency gains.

Concerns about market concentration and its effects on competition are at the heart of antitrust policy. Will Macheel explains the Herfindahl-Hirschman Index (HHI) as a common measure of market concentration, its implications for United States antitrust policy, and potential drawbacks of the measure. He closes the article by highlighting research on the HHI as a regulatory tool for screening mergers.