Mark Weiss

Mark G. Weiss

Baker & McKenzie LLP


Mark Weiss is a partner in the Firm's North America Antitrust & Competition Practice Group. He is an experienced litigator and counselor with proficiency in antitrust litigation, class-action defense, federal multi-district litigation, and no-poach defense. Mark has vigorously and tirelessly represented clients in a variety of industries including manufacturing, mining, high-tech industries, banking, defense contracting, aerospace, and energy.

As an experienced antitrust counsel, Mark has also conducted cartel investigations and internal compliance reviews, and regularly provides antitrust advice on a broad range of non-litigation matters, including sales and distribution advice, antitrust compliance, competitive merger analysis, and merger clearance strategy.

Prior to joining Baker McKenzie, Mark worked at another global law firm with a focus on class-action antitrust litigation, including defending a global electronics manufacturer from price-fixing and collusion claims, defending a major global financial institution from antitrust collusion and boycott claims, and defending a large government defense contractor from claims alleging illegal no-poach agreements.

Practice Focus

Mark's practice focuses on antitrust litigation, both private and public. He assists clients in the defense of class actions, complex civil and criminal investigations, merger challenges, and compliance counseling. He helps clients navigate federal and state regulatory inquiries, enforcement actions and multidistrict antitrust class actions.

Representative Legal Matters

  • Counsel for Defendant in In re: Hard Disk Drive Suspension Assemblies Antitrust Litigation (MDL 2918) in the Northern District of California alleging price-fixing claims.
  • Advised a leading cinema operator on the US antitrust aspects with respect to an acquisition by another leading cinema operator, creating one of the world's largest cinema companies.
  • Advised a global shipping company in a DOJ criminal antitrust investigation.
  • Advised a global publishing company on compliance with a third-party subpoena related to an acquisition in the publishing industry.
  • Advised a bioscience company on the US antitrust aspects of a distribution agreement.
  • Advised a global car rental agency on the US antitrust aspects of advertising restrictions.
  • Advised a manufacturer of consumer products on the US antitrust aspects of commercial distribution contracts and a minimum advertising pricing policy.
  • Advised a global aviation training company on antitrust compliance guidelines and contractual terms.

Prior to joining the Firm, Mark handled the following matters:

  • Counsel for Defendant in In re: Capacitors Antitrust Litigation in the Northern District of California alleging collusion and price-fixing. The client favorably settled with direct and indirect purchaser classes.
  • Counsel for Defendant in Hunter v. Booz Allen Hamilton in the Southern District of Ohio alleging use of illegal no-poach agreements to restrain the employment market for government intelligence services.
  • Counsel for Defendant in In re: Stock Loan Antitrust Litigation in the Southern District of New York alleging collusion and boycott claims in the stock lending market.
  • Counsel for Defendant in Knurr v. Orbital ATK in the Eastern District of Virginia alleging violations of the federal securities laws. The case settled favorably.
  • Counsel for Defendant in Orbital Sciences v. United Launch Alliance in the Eastern District of Virginia alleging exclusionary conduct claims. The case settled favorably.
  • Successfully represented companies in front of the FTC and DOJ to clear mergers or acquisitions in a number of industries including grocery retail, automotive parts manufacturing, pawn shops, and recreational vehicle manufacturing.


  • District of Columbia~United States (2014)
  • Virginia~United States (2013)
  • U.S. District Court, Eastern District of Virginia (2014)
  • U.S. Court of Appeals, Fourth Circuit~United States (2018)


  • George Mason University School of Law (JD, magna cum laude) (2013)
  • Claremont McKenna College (BA Economics & Government) (2007)


  • English