James H. Weingarten is a partner in the Washington, DC office of Milbank LLP and a member of the firm’s Litigation & Arbitration Group.
Primary Focus & Experience
Mr. Weingarten is a seasoned trial lawyer who has served as first chair trial counsel and lead counsel in federal courts and federal agency administrative proceedings. Over the course of his career, Mr. Weingarten has taken a dozen cases to trial and judgment. He has significant experience in antitrust matters, both conduct and merger related, including serving as Chief Trial Counsel for the Federal Trade Commission (FTC), where he litigated and tried the government’s biggest antitrust matters in federal court and administrative proceedings. He has experience litigating competition matters across industries, including the healthcare, pharmaceutical, and technology sectors. He counsels clients on the full spectrum of competition issues, including issues involving AI and algorithmic pricing. He has significant experience with federal and state antitrust enforcement.
Most recently, Mr. Weingarten was lead counsel for the State of California in challenging Paramount Skydance’s $110-billion acquisition of Warner Bros. Discovery. Mr. Weingarten successfully argued for entry of a temporary restraining order. This was the first contested restraining order in a merger case in recent memory and the largest merger ever enjoined in a US court.
At the FTC, Mr. Weingarten led some of the government’s most important merger challenges, including serving as lead lawyer in FTC v. Microsoft Corp. & Activision Blizzard, Inc. (N.D. Cal.); FTC v. The Kroger Co. & Albertsons Cos., Inc. (D. Or.); FTC v. Sanofi & Maze Therapeutics, Inc. (D. Mass.); FTC v. HCA Healthcare & Steward Health Care Systems (D. Utah); FTC v. RWJ Barnabas Health & Saint Peter's Healthcare System (D.N.J.); In re Nvidia Corp., Softbank Group Corp., Arm Ltd. (FTC admin proceeding).*
Mr. Weingarten has substantial experience with Sherman Act claims. He has successfully tried cases challenging exclusive dealing (FTC v. Vyera Pharmaceuticals, LLC, Kevin Mulleady, and Martin Shkreli (S.D.N.Y.)); sham patent litigation (FTC v. AbbVie, Inc. (E.D. Pa.)); and reverse-payment settlements (In re Impax Labs., Inc. (FTC admin proceeding)*. Earlier in his career, Mr. Weingarten was part of the trial team that won a complete defense verdict in the In re Nexium (Esomeprazole) (D. Mass.) class action litigation.*
Since joining Milbank in 2024, Mr. Weingarten has represented clients in government and private litigation. Representative matters include:
- Representation of the State of California in challenging Paramount Skydance’s $110-billion acquisition of Warner Bros. Discovery. Successfully argued for a temporary restraining order enjoining closing. This was the largest merger ever enjoined in a US court.
- Representation of Lennox International, Inc. in defending against class action price-fixing allegations in the HVAC industry. In re HVAC Equipment Antitrust Litigation (E.D. Mich.).
- Successful representation of U.S. Steel in Sherman Act claims against a competitor that arose in connection with Nippon Steel’s acquisition of U.S. Steel. U.S. Steel Corp. v. Cleveland-Cliffs Inc. (W.D. Pa.).
- Successful defense against a competitor’s request for a preliminary injunction in a case challenging an acquisition of an oil terminal and alleging monopolization of fuel markets. See Approved Oil Co. v. Sprague HP Holdings LLC (E.D.N.Y.).
Mr. Weingarten maintains an active pro bono practice, including trial work. For example, he represented a criminal defendant against charges including felony conspiracy and obtained a not guilty verdict on all felony charges.*
