The US Department of Justice (DOJ) and the Federal Trade Commission (FTC) have solicited public comments and are holding joint public workshops to explore the possibility of updating the Horizontal Merger Guidelines that are used by both agencies to evaluate the potential competitive effects of mergers and acquisitions. The goals of the workshops are to determine whether the Horizontal Merger Guidelines accurately reflect the current practice of merger review at the DOJ and the FTC as well as to take into account legal and economic developments that have occurred since the last significant Guidelines revision in 1992. This article from GCP: The Antitrust Chronicle offers suggestions for how the Horizontal Merger Guidelines could be revised. The authors’ comments are based on the idea that the Guidelines would provide more information and guidance if they were revised to reflect the actual practice and analytical process that the agencies employ in evaluating the potential competitive impact of a proposed merger.