Ryan Tansey, former Chief of the DOJ Antitrust Division’s Washington, D.C. Criminal Section, is an antitrust expert and seasoned litigator and trial lawyer in King & Spalding’s New York office. Whether representing clients in high-stakes criminal investigations, parallel class actions, or helping them proactively manage risk, Ryan leverages his substantial first-chair trial experience and a decade at the Department of Justice shaping national antitrust enforcement priorities and leading some of the Department’s most complex matters across multiple components and four presidential administrations.
Ryan’s practice focuses on guiding clients through every phase of criminal and civil antitrust matters, as well as broader commercial disputes and white-collar matters. He represents clients in federal and state investigations, litigates civil class actions, and counsels on antitrust compliance and proactive risk management. As a true first-chair trial lawyer, Ryan is one of very few antitrust experts who also has the skill and experience to lead the most complex cases from inception through to trial and successful jury verdict. He is known for his strategic vision and helping clients formulate a strategy that balances legal risks, collateral consequences, and reputational concerns.
Before joining King & Spalding in June 2026, Ryan served as Chief of the Antitrust Division's largest section in Washington, D.C., where he supervised hundreds of grand jury investigations, charges, plea agreements, and trials nationwide. He oversaw a landmark DPA with Teva Pharmaceuticals, securing a $225 million criminal fine—the largest ever in a domestic antitrust cartel case—with unprecedented criminal divestitures. His team of 90 prosecutors and staff handled matters across industries including technology and AI, telecommunications, healthcare, financial services, energy, and defense contracting. Ryan also helped shape national antitrust enforcement policies, including launching the Division's inaugural Whistleblower Rewards Program, and worked closely with foreign competition authorities, state attorneys general, and federal agencies on parallel investigations.
Earlier in his career, Ryan was a go-to litigator in multiple DOJ components. As a Trial Attorney in the Antitrust Division, he led one of the decade's most significant international cartel prosecutions, resulting in five corporate convictions and over $363 million in penalties. As an Assistant U.S. Attorney, he led an office and prosecuted complex cases ranging from securities fraud and bribery to murder-for-hires and large pill mill prosecutions. He has also led many complex trials to favorable verdicts and received numerous DOJ accolades for his trial work, including the EOUSA Director's Award and selection as a returning instructor at DOJ's criminal trial advocacy course.
Prior to DOJ, Ryan practiced at another leading international law firm, defending clients in civil and criminal antitrust matters, including MDLs, class actions, and investigations concerning LIBOR, Forex, interchange fees, and global shipping.
