Biography
During his time at the FTC, Mark oversaw hundreds of merger investigations and, in his most recent position as head of the Mergers IV Division, was the lead government enforcer for transactions in a broad variety of sectors including the retail, consumer products, grocery, casino, and health care services industries. His agency experience has allowed him to work closely with regulators around the world, developing relationships that are invaluable given the increasing globalization of the merger review process. Likewise, Mark has also worked closely with state-level antitrust enforcers, especially as many state attorneys general have become more active in antitrust enforcement. Mark’s participation in the development of the FTC’s merger enforcement priorities, litigation strategies, and theories of antitrust harm allow him to provide practical, real-world guidance clients need to inform their business and M&A strategies.
Beyond his role as an antitrust enforcer, Mark has also been a first-chair litigator with extensive trial experience in FTC merger cases. He has played a leading role in several of the FTC’s most prominent merger litigations, including Sysco/US Foods, Cabell Huntington Hospital/St. Mary’s Medical Center, DraftKings/FanDuel, and J.M. Smucker/Conagra. He served as lead trial counsel in the FTC’s federal court challenges of Jefferson Health/Einstein Healthcare Network and Louisiana Children’s Medical Center/HCA, and he supervised numerous additional merger investigations and litigations across a range of industries.
Mark also guided numerous merger investigations to consent agreements while at the Commission. These settlements enabled mergers to proceed following divestitures of assets that created antitrust concerns. Although such consent agreements have been subject to increased scrutiny by the antitrust agencies, Mark has successfully negotiated and navigated the Commission’s internal process to finalize these settlements. Under the current administration, Mark and his team handled the consent agreements in Price Chopper/Tops and Tractor Supply/Orscheln, two of a small number of merger consents approved in recent years.
In addition to his leadership experience at the FTC, Mark has held several other key roles in government. For two years, Mark was Counsel to the Director of the Bureau of Competition at the FTC, where he advised the Bureau’s leadership and worked closely with agency officials, including the Commissioners’ offices, the Office of General Counsel, and the Office of Policy Planning. Mark also served as a Special Assistant U.S. Attorney in the District of Columbia. In this role, Mark first-chaired approximately two dozen criminal bench trials. Mark began his antitrust career as a staff attorney in the FTC’s Mergers I Division, where he investigated mergers involving pharmaceuticals, medical devices, defense and aerospace products, Internet technology, and industrial services.
Mark has been a leading voice in competition policy across the federal government, with state governments, and internationally. As the leader of the Mergers IV Division, Mark was frequently called upon to brief the House Judiciary Committee and the Senate Commerce Committee on his division’s investigations and competition policy issues. He also interacted with state attorneys general on investigations and policy issues, and he testified at public hearings as an FTC representative. Mark has also engaged with competition enforcers across the globe, including the European Commission, the United Kingdom, Canada, and Brazil.
Over the course of his career in government, Mark has been a frequent commentator, both as a speaker and writer. Mark has been a six-time panelist at the ABA Antitrust Section’s Spring Meeting, the premier annual antitrust conference. He has also spoken to broader audiences in podcasts and at gatherings of in-house counsel. Multiple publications have highlighted Mark’s work and its impact, including The Antitrust Source, which published his co-authored article, “DraftKings/FanDuel: Adventures in Challenging a Merger Using an Effects-Driven Approach.” The FTC has repeatedly recognized Mark’s accomplishments and expertise and he is a four-time recipient of the agency’s Janet Steiger Team Award and a three-time recipient of the agency’s Award for Superior Service. In 2009, he was the recipient of the agency’s Director’s Award and in 2008, he received the agency’s Award for Meritorious Service.
Mark is an active member of the American Bar Association, Section of Antitrust Law and the American Health Law Association.
Firm News & Announcements, Latest Thinking
Firm News & Announcements
- Weil Advises Goldman Sachs Alternatives in Acquisition of a Majority Stake in Sila Services Deal Brief — November 11, 2024
- Weil Reinforces Leading Global Antitrust Group with Addition of FTC Veteran Mark Seidman Press Release — September 04, 2024
Latest Thinking
- Antitrust Enforcement in Labor Markets: Merger Analysis at a Time of Agency Transition Alert — By John P. Barry, Megan A. Granger, Adam C. Hemlock, Eric S. Hochstadt, Brianne Kucerik, Michael Moiseyev, Jeffrey H. Perry, Jasmine Rosner, Kristin Sanford, John E. Scribner, Mark Seidman, Rebecca Sivitz, Jeff L. White, Joe Ehrenkrantz and Katie Rider — PDF — December 10, 2024
- Antitrust Enforcement in Trump’s Second Term: Policy Changes, Enforcement Priorities, and Leadership Turnover Alert — Antitrust — By Megan A. Granger, Adam C. Hemlock, Eric S. Hochstadt, Brianne Kucerik, Michael Moiseyev, Jeffrey H. Perry, Jasmine Rosner, Kristin Sanford, John E. Scribner, Mark Seidman, Jeff L. White, Charlotte McFaddin and Michael Geisler — PDF — November 18, 2024
- New HSR Rules, and Impact of Change in Administration Alert — Antitrust — By Megan A. Granger, Adam C. Hemlock, Eric S. Hochstadt, Brianne Kucerik, Michael Moiseyev, Jeffrey H. Perry, Jasmine Rosner, Kristin Sanford, John E. Scribner, Mark Seidman, Jeff L. White, Carla A. R. Hine and Michael C. Naughton — PDF — November 14, 2024