A&O Shearman

A&O Shearman's antitrust practice sits within its wider commercial litigation department and focuses on high-risk disputes and investigations. The team defends multinational corporates and financial institutions in civil litigation, criminal proceedings, and regulatory matters, with experience in class actions, MDLs, merger challenges, cartel allegations, and monopolization claims. The practice is trial-ready and often engaged where cases raise commercial and regulatory exposure, requiring coordination with both the US and cross-border teams. US head of antitrust litigation Todd Stenerson, who is based in Washington, DC, has three decades of experience defending antitrust claims and leading matters involving the DOJ and FTC. Noah Brumfield works between Washington, DC and Silicon Valley, advising clients on global antitrust strategy and representing them before enforcement agencies. Richard Schwed focuses on price-fixing, collusion, monopolization, and financial-markets disputes in New York. Assisting in New York is Brian Hauser, who acts in antitrust litigation, while Rachel Mossman Zieminski works from the Dallas office and is recognized for defense work in no-poach cases, IP-related antitrust claims, and DOJ merger trials. Kathryn Mims joined the Washington, DC team in April 2026.