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John Terzaken is Global Co-Chair of the Firm’s Antitrust and Trade Regulation Practice. John represents domestic and international clients in government enforcement and private litigation of cartel and other alleged antitrust violations, market sector investigations and antitrust compliance, encompassing all major industry sectors, including financial institutions, pharmaceutical, professional services, manufacturing, energy, shipping, food and beverage, and many others.

John’s work highlights include defending:

  • Tyson Foods in a wage fixing antitrust class action alleging a decade-long conspiracy to fix wages.
  • 21st Century Oncology in a civil suit alleging monopolization and attempted monopolization in violation of Sherman Act Section 2.
  • A global financial institution in criminal investigations and related follow-on civil class action litigation involving trading of securities.
  • An international consumer foods corporation in a criminal antitrust investigation and related follow-on civil class action litigation involving the seafood industry.
  • Micron in antitrust class actions alleging collusion of DRAM products.
  • A national healthcare provider in a criminal antitrust investigation into physician services.

Prior to joining Simpson Thacher, John held a leading position in the DOJ’s Antitrust Division as Director of Criminal Enforcement, where he oversaw the Division’s criminal enforcement nationwide. His range of responsibilities included presiding over some of the largest global cartel investigations ever undertaken by the DOJ. He also served as the Division’s chief liaison with domestic and international law enforcement authorities, as well as the Financial Fraud Coordinator for inter-agency prosecutions and investigations. John’s DOJ service earned him awards of distinction from the Attorney General of the United States and the Assistant Attorney General for the Antitrust Division.

He is consistently recognized as a leading antitrust lawyer (Band 1) by both Chambers Global and Chambers USA, where clients describe him as “one of the strongest lawyers I have ever worked with,” “. . . a superb lawyer in the cartel space,” an attorney who “knows the technical aspects of antitrust law and also how to intuitively apply that to business realities,” and has a “wonderful working manner with clients and government figures.” John is also recognized in The Legal 500 U.S.’s “Hall of Fame.”

John is a member of the Antitrust Sections of the American Bar Association (ABA) and International Bar Association (IBA) and is presently serving an appointment by the ABA on the International Cartel Task Force. He regularly writes and speaks on antitrust matters for industry publications and events, including serving as the Co-Editor of The Cartels and Leniency Review.

John received his J.D. from University of Virginia School of Law, where he was on the Editorial Board of the Virginia Law Review. He received his B.A., magna cum laude, from American University in 1996.


Updated Sep 2021