Katharine O’Connor focuses her practice on complex antitrust litigation, government investigations, defending mergers and acquisitions before antitrust enforcement agencies, and counseling clients on antitrust compliance issues. She has experience representing clients in a wide array of industries, including health care, manufacturing, food and finance

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  • Defeated certification on impact and damages of proposed direct purchaser class in In re Steel Antitrust Litigation, which was the largest class action in the country when it was filed, and in which plaintiffs claimed damages in excess of a $17 billion for alleged price fixing and coordinated capacity restrictions
  • Achieved dismissal with prejudice on behalf of joint defense group, which was affirmed by the Seventh Circuit, of all indirect purchaser claims in In re Steel Antitrust Litigation
  • Achieved dismissal with prejudice on behalf of a Group Purchasing Organization (GPO) in a case alleging a vertical conspiracy under the antitrust laws between medical device manufacturer, distributors, and GPOs

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  • The Legal 500 United States, Next Generation Partner, 2020 and 2021
  • Super Lawyers, Illinois Rising Star in Antitrust Litigation 2018 and 2019
  • Benchmark Litigation 2020, Future Star and 40 and Under Hotlist


  • American Bar Association, Section of Antitrust Law and Health Care & Pharmaceuticals Committee


University of Illinois College of Law, JD, summa cum laude, Order of the Coif, 2010
University of Chicago, BA, with honors, 2001


US Court of Appeals for the Seventh Circuit
US District Court for the Central District of Illinois

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Katharine O’Connor

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