Stephen Medlock is a partner in Mayer Brown's Washington DC office. He focuses his practice on antitrust litigation and criminal investigations, with an emphasis on the overlap between antitrust and intellectual property law and high-technology markets. He handles all substantive aspects of antitrust matters, including drafting dispositive motions, planning and executing discovery strategies, taking and defending depositions, working with expert witnesses, preparing witnesses to testify at trial and before grand juries, advocating before the US Department of Justice and Federal Trade Commission, and counseling clients concerning on-going antitrust risks. His depositions and briefs have been quoted in the Washington Post, the New York Times, The Atlantic, and the Baltimore Sun.

Antitrust-IP Litigation and Counseling. Stephen regularly represents clients in antitrust litigation that overlaps with the use and acquisition of intellectual property rights. These cases frequently involve claims that a dominant firm has denied a rival access to a portion of a proprietary system or that a company with a sizeable market share and strong intellectual property rights has engaged in monopolization. Stephen has litigated for both plaintiffs and defendants in these antitrust-IP cases. In addition, Stephen often counsels companies on the antitrust risks associated with licensing or refusing to license patents.

Antitrust Litigation. Stephen’s representations have included some of the largest antitrust and unfair competition cases filed by private plaintiffs and the class action bar. These matters have included a variety of legal theories including price-fixing, monopolization, exclusive dealing, tying, Robinson-Patman Act violations, patent misuse, and business torts. Recently, Stephen helped obtain summary judgment for Nestlé USA in In re Chocolate Confectionery Antitrust Litigation, one of the largest multi-district antitrust class actions to date. In 2015, Global Competition Review nominated In re Chocolate Confectionery Antitrust Litigation as “Litigation of the Year, Cartel Defense: Creative, Strategic, and Innovative Litigation on Behalf of a Defendant.”

Criminal Antitrust Investigations. Stephen regularly defends organizations and individuals facing criminal antitrust investigations. He assists in conducting sensitive internal investigations, counseling clients on potential criminal exposure, advocating for clients before the US Department of Justice, and preparing individuals to testify before grand juries. In addition, Stephen has authored multiple articles concerning how organizations should respond to search warrants executed in antitrust investigations. Many of these criminal matters have been resolved without indictment.

Stephen regularly participates in the American Bar Association’s Section of Antitrust Law where he is a Vice Chair of the Exemptions & Immunities Committee and the co-editor of the forthcoming third edition of the Noerr-Pennington Doctrine treatise.

Spoken Languages

  • English
  • Russian


  • In re Chocolate Confectionery Antitrust Litigation, 999 F. Supp. 2d 777 (M.D. Pa. 2014), aff’d 801 F.3d 383 (3d Cir. 2015). Mayer Brown litigators helped secure a significant summary judgment and appellate victories for Nestlé USA in one of the largest multi-district antitrust litigations to date in the United States. The litigation consisted of over 90 federal lawsuits and alleged a conspiracy with Mars, Hershey, and Cadbury to fix the price of chocolate candy products sold in the United States. These complaints were brought on behalf of direct and indirect purchasers and large individual corporate plaintiffs, such as Safeway, Kroger, and CVS. The Third Circuit affirmed, unanimously holding that “[a] conspiracy elsewhere, without more, generally does not tend to prove a domestic conspiracy, especially when the conduct observed domestically is just as consistent with lawful interdependence as with an antitrust conspiracy.”
  • Masimo Corporation v. Philips Electronics North America Corporation, 2015 WL 2406155 (D. Del.). Represented Philips Electronics North America Corporation in connection with antitrust-IP claims for monopolization, attempted monopolization, conspiracy to monopolize, tying, group boycott, restraint of trade, and patent misuse.
  • Nespresso USA v. Ethical Coffee Company SA, --- F. Supp. 3d ---, 2017 WL 2984072 (D. Del.). Representing Nespresso USA and Nestlé Nespresso S.A. in antitrust-IP case concerning the design of Nespresso’s Original Line espresso machines. Secured dismissal of Swiss Nestlé entities for lack of personal jurisdiction and won dismissal of Lanham Act counterclaim at the pleading stage.
  • tyntec Inc. v. Syniverse Technologies, LLC, 2017 WL 2733763 (M.D. Fla.). Representing tyntec Inc. and tyntec Group Ltd. in connection with antitrust claims for monopolization and attempted monopolization of the high-tech market for sending and hosting text and video message traffic.
  • In re Broiler Chicken Antitrust Litig. (N.D. Ill.). Representing Foster Farms, LLC against multiple class actions alleging that the major U.S. chicken companies conspired to restrict output and fix prices.
  • Sterling Merchandising, Inc. v. Nestlé S.A., 656 F.3d 112 (1st Cir. 2011). Represented Nestlé, S.A. and local affiliates in appeal before First Circuit, which affirmed summary judgment in complex antitrust action involving alleged monopolization and exclusionary practices in the distribution of ice cream.
  • Nirvana, Inc. v. Nestlé Waters North America Inc., 123 F. Supp. 3d 357 (N.D.N.Y. 2015). Secured dismissal of  Robinson-Patman Act, predatory pricing, commercial bribery, exclusive dealing, and tortious interferences claims against Nestlé Waters North America at the pleading stage.
  • Massengale v. City of Jefferson, Missouri, 2011 WL 3320508 (W.D. Mo. 2011). Represented Republic Services and won summary judgment on all antitrust claims, including allegations that Republic Services violated Sections 1 and 2 of the Sherman Act.
  • Zayed v. Associated Bank, N.A., 2017 WL 424855 (D. Minn.). Won summary judgment for Associated Bank in connection with claims that bank aided and abetted $190 million Ponzi scheme.  Case is currently on appeal to the Eighth Circuit.
  • Automotive Parts Antitrust Investigation. Represented multiple executives alleged to have conspired abroad to fix the prices of automotive parts destined for the US market.
  • Freight Forwarders Antitrust Investigation. Represented organization and executive in criminal investigation and subsequent civil litigation.
  • In re Grand Jury Proceedings. Represented client in successful invocation of act of production privilege in response to grand jury subpoena issued by Public Integrity Section of the US Department of Justice.
  • Non-Public Antitrust Audit. Conducted internal investigation and enhanced antitrust compliance procedures for multi-billion dollar automotive parts company.


American University Washington College of Law, JD, cum laude, Mooer's Trophy for Oustanding Student in Trial Advocacy; Journal of Sustainable Development Law and Policy (2007-2008)

Georgetown University, BSFS, International Politics


  • District of Columbia
  • Virginia


  • US Supreme Court
  • US Court of Appeals for the Eleventh Circuit
  • US Court of Appeals for the Third Circuit
  • US Court of Appeals for the Eighth Circuit
  • US District Court for the District of Columbia