coordinated and unilateral competitive effects of merger. The central issue considered is when and how market shares, and market … concentration statistics derived from them, form an appropriate basis for presuming harm to competition from merger. This revision …

The DOJ-FTC Merger Guidelines were developed for and best deal with horizontal mergers where the theory of harm is … coordinated effects. The Guidelines deal awkwardly, at best, with mergers where the theory of harm is unilateral effects. The … needed for inquiry and enforcement where the theory of harm is unilateral effects, as is a market definition paradigm for …

, merger laws and enforcement practices, econometric methods for analyzing prospective horizontal mergers, and evidence …

The past forty years have witnessed a remarkable transformation in horizontal merger enforcement in the United States … using merger enforcement data and a survey we conducted of merger practitioners that the decline in antitrust enforcement is … ongoing, especially at the current Justice Department. We then argue in favor of reinvigorating horizontal merger enforcement …

conduct merger simulations and why there are important antitrust issues related to integrating merging parties’ pricing … effects in a merger context.- Remedies. Why data compatibility and collusion risk are important considerations when “divesting …