WASHINGTON (Diya TV) — Mark Hamer, the second-in-command at the U.S. Justice Department’s Antitrust Division, has announced his departure from the Trump administration after nearly a year in the role. His exit marks another leadership change at a time when federal antitrust enforcement has remained in sharp focus across multiple industries.
Hamer, who served as a deputy assistant attorney general, shared the news Monday in a post on LinkedIn. He said he had committed to one year of public service when he accepted the position and has now completed that term.
“I committed to a year of public service when I accepted this role,” Hamer wrote, confirming that his time at the Justice Department was planned from the start.
His departure comes as the Antitrust Division continues to pursue major competition cases involving some of the most powerful sectors of the U.S. economy.
As the second-ranking official in the Antitrust Division, Hamer played a central role in shaping and executing the enforcement strategy. He joined the Justice Department in March last year as one of four deputy assistant attorneys general overseeing antitrust work. In his position, Hamer supervised litigation and civil enforcement matters. He worked closely with career attorneys and leadership to advance cases tied to market competition and consumer protection.
During his tenure, the division focused on industries that affect everyday Americans. These included technology, health care, entertainment, agriculture, real estate, and financial services. Many of these sectors face growing scrutiny from regulators over pricing power, mergers, and market dominance.
“Our enforcement cases and investigations targeted high-profile competition concerns,” Hamer said in his post, highlighting the broad scope of the division’s work.
The Antitrust Division has remained active in recent years as federal officials push for tougher oversight of large corporations. Technology companies, in particular, have drawn attention over concerns about monopolistic practices and reduced consumer choice. Health care has also stood out as a priority area. Rising medical costs and consolidation among hospitals and insurers have placed competition policy at the center of national debate.
Agriculture and real estate markets have faced similar concerns. Lawmakers and regulators have questioned whether consolidation limits options for farmers, homebuyers, and renters. Financial services and entertainment have also seen closer review, especially as companies grow larger through mergers. Hamer oversaw litigation tied to these issues, helping guide the government’s legal strategy in complex antitrust cases.
After leaving the Justice Department, Hamer will return to private practice at Baker McKenzie. He previously served as global chair of the firm’s antitrust and competition practice before joining the government.
His move reflects a common path for senior antitrust lawyers, who often shift between public service and private practice. At Baker McKenzie, Hamer is expected to advise corporate clients on competition law, merger review,s and regulatory compliance. The firm is one of the world’s largest law practices, with a strong presence in antitrust and international competition matters. Hamer’s experience inside the Justice Department adds to his profile as a leading figure in the field.
Hamer’s exit leaves the Antitrust Division with one fewer senior official overseeing enforcement. The division operates under the Justice Department and plays a critical role in enforcing U.S. antitrust laws, including the Sherman Act and the Clayton Act.
The Trump administration has taken a mixed approach to antitrust policy, supporting some high-profile enforcement actions while also promoting deregulation in other areas. Leadership changes can influence how aggressively the division pursues cases and how it prioritizes industries. Justice Department officials have not yet announced who will take over Hamer’s responsibilities or whether a replacement will be named soon.
Hamer’s departure comes at a moment when antitrust policy continues to attract public attention. Both lawmakers and consumers are watching how the government responds to market concentration and corporate power. While Hamer’s term was limited by design, his work helped shape ongoing investigations and cases that will continue after his exit. These efforts aim to protect competition and ensure fair markets across the economy.
As he returns to private practice, Hamer leaves behind a Justice Department still deeply engaged in antitrust enforcement, with cases that could have lasting effects on major U.S. industries.
