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...

Economists widely agree that, absent sufficient efficiencies or other offsetting factors, mergers that increase concentration substantially are likely to be anticompetitive. Further, holding everything else equal, the magnitude of anticompetitive effects tends to be larger, the larger is the...

This Feature summarizes why and how vertical merger enforcement should be invigorated. In our modern market system, vigorous vertical merger enforcement is a necessity. Strong enforcement is particularly important in markets where economies of scale and network effects lead to barriers to entry...

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...

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...

These comments (originally submitted to the DOJ and FTC in November 2009) make a number of comments relevant to revising the Merger Guidelines. The comments focus on the use of the GUPPI (gross upward pricing pressure index) in unilateral effects analysis. They also comment on the deterrence and...

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...