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...

This comment responds to the request by the Federal Trade Commission and the Department of Justice’s Antitrust Division for public comment on the draft 2020 Vertical Merger Guidelines. In this comment, we show that there is an inherent loss of an indirect competitor and competition when a...

Most quantitative tools for assessing competitive effects of mergers rely heavily on recapture ratios (also known as aggregate diversion ratios). Recapture ratios measure the proportion of customers switching away from a product that is captured by other products within the market rather than...

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...

On March 20, 2011, wireless provider AT&T announced its intention to merge with T-Mobile USA, a competing wireless provider. This article reviews the economic analysis of this proposed acquisition that we carried out for Sprint and explains why the merger would have been anticompetitive. We...