Mark Hamer

Mark Hamer

Baker & McKenzie LLP


Mark H. Hamer is Global Chair of the Firm's Antitrust & Competition Practice Group, comprised of over 300 competition lawyers in over 60 offices across 43 countries. Mark has over 25 years of wide-ranging litigation experience, including first-chair roles in jury trials, bench trials and arbitrations. His primary focus is antitrust litigation.

Before joining Baker McKenzie, Mark was a successful federal prosecutor in the Antitrust Division of the US Department of Justice. He was involved in some of the DOJ's highest-profile antitrust trials. Before joining the DOJ, Mark was a partner at another global law firm where he handled complex multidistrict antitrust class actions in courts across the nation.

Practice Focus

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

As an experienced antitrust counsel, Mark also regularly provides antitrust advice on a broad range of non-litigation matters, including antitrust deal support, merger clearance strategy, sales and distribution advice, and antitrust compliance.

Mark is seasoned in a diverse array of industries, including payments, financial services, energy, rail and truck systems, computer hardware and software, consumer products, movie theaters, satellite broadcasting and insurance.

Representative Legal Matters

  • Lead counsel for defendant in In re: Hard Disk Drive Suspension Assemblies Antitrust Litigation (MDL 2918) in the Northern District of California.

  • Lead counsel for a global urethane manufacturer in antitrust litigation in the Eastern District of New York alleging a group boycott.

  • Antitrust counsel for global ocean shipping company in US DOJ cartel investigation.

  • Lead counsel for German railway component manufacturer in In re Railway Industry Employee No-Poach Antitrust Litigation (MDL 2850) in the Western District of Pennsylvania, and lead counsel in related investigation and litigation by US DOJ’s Antitrust Division in the District of Columbia.

  • Lead counsel for medical device manufacturer in antitrust litigation alleging monopolization in the Western District of Texas.

  • Served as lead antitrust trial counsel in patent infringement and antitrust matter for leading global oil well remediation company. The matter was tried in Houston federal court in 2018, resulting in complete victory including a defense verdict on all antitrust counterclaims.

  • Served as lead US antitrust counsel for multinational filtration company in USD 4.3 billion sale to competitor.

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

  • Served as DOJ trial counsel in a two-month antitrust trial concerning credit card anti-steering rules, affecting over USD 50 billion in commerce.

  • Served as DOJ trial counsel in the challenge to a multinational manufacturer's USD 3 billion acquisition in the home appliances industry.

  • Served as DOJ trial counsel in the enforcement action to enjoin the merger of the nation's top two cinema advertising networks.


Professional Honors

  • US Attorney General's Distinguished Service Award, 2015
  • US DOJ Antitrust Division Team Award of Distinction (2 awards), 2015
  • US DOJ Antitrust Division Award of Distinction for Individual Achievement, 2011


  • District of Columbia~United States (2017)
  • California~United States (1991)


  • University of Virginia School of Law (J.D.) (1991)
  • University of Virginia (B.A. with High Distinction) (1988)


  • English
  • Speaker and Panelist, "Current Developments in German, European and Global Antitrust Law 2019" (Aktuelle Entwicklungen Kartellrecht 2019), Association of Corporate Counsel Competition Law Update, Munich, Germany, 24 September 2019

  • Speaker, "Antitrust Litigation: The International Picture," London Annual Corporate Compliance Seminar, London, UK, 23 September 2019

  • Speaker, "Navigating Antitrust Investigations and Class Actions Globally: Risks and Strategies," Keidanren Global Competition Law Conference, Tokyo, Japan, 8 July 2019

  • Plenary Session Speaker and Moderator, "Multi-Sided Platforms: Clarity or Confusion?" GCR Live 8th Annual Antitrust Law Leaders Forum, Miami, FL, 1 February 2019

  • Speaker, "America First: U.S. Antitrust Developments in the Trump Era," VVM Dutch Competition Law Association, Amsterdam, the Netherlands, 14 November 2018