In this short and mainly expository article, we explain the “hypothetical monopolist test” that has become the standard methodology for identifying relevant antitrust markets in merger cases, and discuss two approaches to implementing the test. We then focus on the implementation of the test...

Private antitrust litigation often involves a dominant firm being accused of exclusionary conduct by a smaller rival. In such cases, the defendant generally has a much larger financial stake in the outcome. We explore the implications of this asymmetry in a model of litigation with endogenous...

The FTC and DOJ requested comments on their draft Vertical Merger Guidelines in January 2020. This article is a complete alternative set of suggested Vertical Merger Guidelines that reflects and supplements the approach explained in the comments submitted by the author along with Jonathan....

This article analyzes my short proposal for reviewing and modifying merger consent decrees to permit additional relief if the provisions of the initial consent merger are found to fail to preserve or restore competition in a reasonable period of time after the merger was consummated. My proposal...

This article seeks an answer to a question that should be well settled: for purposes of antitrust analysis, what is 'market power' and/or 'monopoly power'? The question should be well settled because antitrust law requires proof of actual or likely market power or monopoly power to establish...

Mergers and acquisitions are a major component of antitrust law and practice. The U.S. antitrust agencies spend a majority of their time on merger enforcement. The focus of most merger review at the agencies involves horizontal mergers, that is, mergers among firms that compete at the same level...

There seems to be consensus that the Department of Justice's 1984 Vertical Merger Guidelines do not reflect either modern theoretical and empirical economic analysis or current agency enforcement policy. Yet widely divergent views of preferred enforcement policies have been expressed among...

It has been one hundred years since the end of the Progressive Era and twenty years since the Microsoft settlement. This twenty-year period has seen the rise of the Internet and a new set of dominant platforms, as well as increased consolidation in the brick-and-mortar world. Antitrust has...