Stephen Weissman, former Deputy Director for the Federal Trade Commission’s Bureau of Competition, is a Washington, D.C.-based partner and one of the cornerstones of the firm’s Antitrust and Competition Practice Group. A former top antitrust enforcer and accomplished defense lawyer, Steve brings exceptional experience and a practical approach to representing companies in antitrust investigations by the FTC and U.S. Department of Justice and high-stakes antitrust litigations. Chambers USA describes him as “a fantastic lawyer” and a “tour de force.” Who’s Who Legal – Competition (2022) identifies him as a “super star in the market who works on some of the most challenging” matters. In 2024, MergerLinks named Steve one of the “Top 10 Antitrust Lawyers in North America.”
While serving as FTC Deputy Director from 2013-2015, Steve was involved in and supervised all of the agency’s merger and non-merger investigations and litigations, spanning a wide range of industries, including pharmaceuticals and other healthcare segments, digital and high-tech markets, consumer products, energy, and chemicals. Steve served as lead trial counsel in the FTC’s successful challenge to the $3.5 Billion acquisition by Sysco Corp. of U.S. Foods, Inc.
Before joining Gibson Dunn, Steve co-chaired the Antitrust and Competition practice at another global law firm, where he served as one of the lead lawyers in a number of headline and high-stakes antitrust cases. In 2016, National Law Journal named Steve an “Antitrust Trailblazer” and Global Competition Review named him as a finalist for both its “Lawyer of the Year” and “Litigator of the Year” awards.
He has tried several cases including both bench and jury trials, argued appeals in multiple U.S. Courts of Appeal, and litigated claims under the Sherman Act, Clayton Act, and Robinson-Patman Act, as well as breach of contract and business tort claims.
Steve is regularly recognized as a leading antitrust practitioner by national legal ranking publications, including Chambers USA (2016-2024), Legal 500 (2013, 2015-2024), Best Lawyers in America (2020-2025), Who's Who Legal - Competition (2022-2024), Litigation (2017-2024) and Commercial Litigation (2023), Super Lawyers (2018-2024), Guide to the World's Leading Competition and Antitrust Lawyers (2012, 2013, 2018-2023), and Lawdragon's "500 Leading Litigators in America" (2023-2025) and "500 Leading Antitrust and Competition Lawyers" for 2025.
Representative matters include*
- Represented Broadcom in the FTC’s investigation of the company’s business practices, which resulted in closing of several investigations and settlement of a narrow set of allegations.
- Represented Pioneer Natural Resources in the FTC’s conditional approval of its $63 Billion merger with Exxon Mobil Corp.
- Represented Celgene in the FTC’s conditional approval of its $74 billion acquisition by Bristol-Myers Squibb.
- Represent RealPage, Inc. in multi-district class actions and government litigations alleging “algorithmic pricing” and represented RealPage in the DoJ’s unconditional approval of its 2017 acquisition of Lease Rental Options (LRO).
- Represented Boehringer Ingelheim in the FTC’s in-depth review of its $12.5 billion global asset swap with Sanofi and in antitrust class actions involving alleged monopolization of certain markets based on FDA Orange-Book listings.
- Represented Whirlpool in the Department of Justice’s in-depth review of its acquisition of Maytag Corp.
- Represented PepsiCo and its Frito-Lay business in the FTC’s review and clearance of its acquisitions of Siete Foods (2024) and of the Popcorners business from BFY Brands (2020).
- Lead counsel for Novartis’ Sandoz division in the In re Humira Antitrust Litigation putative class action, including before the Seventh Circuit Court of Appeals, which affirmed dismissal of the complaint.
- Represented Arch Resources in its multi-billion dollar merger with Consol Energy to form Core Natural Resources.
- Lead counsel for Merck & Co., Inc. in In re Nexium Antitrust Litigation (D. Mass) and in various acquisitions, including of Acceleron, Prometheus Bio, Arqule, Imago BioSciences, Virbac’s Sentinel business, and Elanco’s aquaculture business.
- Represented DaVita, Inc. in the FTC’s review of its joint venture with Medtronic, Inc. and of DaVita’s acquisition of University of Utah’s dialysis business.
- Lead counsel for Hartford HealthCare and its affiliates in private antitrust litigation brought by a competitor and in a separate antitrust action brought by a putative class of consumers.
- Lead trial counsel for the FTC in the agency’s successful challenge to Sysco’s proposed $3.5 billion acquisition of US Foods.
- Represented General Electric in its acquisition of BK Medical, Inc.
- Successfully defended Arch Coal in a challenge by the Federal Trade Commission to the company’s acquisition of Triton (D.D.C.), and then in defending Arch’s proposed joint venture with Peabody Energy (E.D. Mo.).
- Successfully defended Anheuser-Busch, Inc. in its merger with InBev, including defeating a private lawsuit to enjoin the merger (E.D. Mo.).
- Represented QVC Corp. in its acquisition of Home Shopping Network (HSN).
- Represented Indorama Ventures Ltd. in a number of transactions, including FTC approval of its joint venture with other PET resin manufacturers and its acquisition of Huntsman’s specialty chemical business.
- Represented Schering Plough in its merger with Merck & Co., Inc.
- Retained by Halliburton Co. to defend in litigation the company’s proposed acquisition of Baker Hughes, Inc.
*****Includes matters handled prior to joining Gibson Dunn
Steve received his law degree from the University of Pennsylvania and earned a BA in Economics from Tufts University. He is admitted to practice in Maryland, the District of Columbia, the United States Courts of Appeals for the Fourth, Sixth, Seventh, and Eleventh Circuits, and the United States District Courts for the District of Maryland, District of Columbia and the Eastern District of Virginia.
Capabilities
Credentials
Education:
- University of Pennsylvania - 1994 Juris Doctor
- Tufts University - 1991 Bachelor of Arts
Admissions:
- District of Columbia Bar