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Dennis McWeeny is a Manager in the Antitrust and Competition Practice. He specializes in the economic analysis of complex antitrust matters, including multinational mergers and acquisitions, as well as matters involving allegations of monopolization and attempted monopolization. Dr. McWeeny has worked on high-profile antitrust matters in a variety of industries, including air transportation, insurance broking, music streaming, wireless communications, agriculture, chemical manufacturing, amusement parks, digital advertising, and big tech. He has led teams of consultants and economists supporting clients and experts through all phases of merger investigations and litigation.

Dr. McWeeny received his PhD from the University of Wisconsin–Madison, where he taught undergraduate courses in microeconomics, industrial organization, data analytics, and econometrics. Dr. McWeeny’s dissertation research focused on antitrust issues in the airline industry, especially spatial competition and the role of geographic market definition in merger evaluation. He has also conducted research on the healthcare industry.


PhD, Economics, University of Wisconsin–Madison

MS, Economics, University of Wisconsin–Madison

BS, Economics and Mathematics (highest distinction), University of Iowa

Selected Work

Selected Experience

  • On behalf of JetBlue Airways in United States et al. v. JetBlue Airways and Spirit Airlines, led the team supporting the expert’s analysis of the likely competitive effects of the proposed merger between JetBlue and Spirit. 
  • In a matter involving the advertising industry, supported the expert’s analysis of competition.
  • On behalf of the United States Department of Justice (DOJ) in the matter United States et al. v. Google LLC, supported the expert’s analysis of claims that Google illegally maintained monopolies in the markets for general search services, search advertising, and general search text advertising. 
  • On behalf of insurance broker Willis Towers Watson during its proposed merger with Aon, assisted the client with responses to the Second Request issued by the DOJ. Developed econometric analyses addressing product market definition and the likelihood of unilateral effects for groups of targeted customers. Assisted with presentations to staff at the DOJ’s Antitrust Division. 
  • For a partial acquisition in the wireless communications industry, supported the expert’s analysis of potential competitive effects arising from vertical integration.
  • On behalf of Evonik in its litigation with the Federal Trade Commission (FTC) over its proposed merger with PeroxyChem, supported the testifying expert in analyzing the likely competitive effects of the merger. 
  • In an intellectual property matter involving music royalty payments, processed and analyzed daily stream counts for tens of millions of tracks of music, with a focus on the entry of new tracks and the distribution of their plays over time. 
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