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Sonia Lahr-Pastor represents clients in antitrust matters before government agencies and in federal court. She has experience litigating bundling and tying cases, monopolization claims, class actions, multi-district litigations, conspiracy and cartel cases, and other complex antitrust litigation. Ms. Lahr-Pastor also represents clients in investigations before the Department of Justice and the Federal Trade Commission, including responding to Second Requests and Civil Investigative Demands. She has represented clients across a number of industries, including pharmaceuticals, biotechnology, auto parts manufacturing, and sports. She also has expertise in the antitrust considerations relevant to multi-sided and digital platforms.


Pro Bono

  • Represented class of migrant mothers and children who had made a preliminary showing of eligibility for asylum in a case challenging the United States’ policy of detaining such mothers and children solely to deter additional immigration.

Previous Experience

  • Judge Richard A. Posner and Professor William M. Landes, University of Chicago Law School, Chicago, IL, Chief Research Assistant (2009-2010)