Sean R. Matt

Seattle, Washington
(206) 268-9327
Practice Areas

Securities Litigation

Class-action Litigation

Consumer Protection

Antitrust Litigation




Indiana University, B.S., Finance, Highest Distinction, 1988

University of Oregon School of Law, J.D., Order of the Coif, Associate Editor of the Law Review, 1992


Sean R. Matt is a partner at Hagens Berman, where he has worked since its founding in 1993. Mr. Matt's practice focuses on multi-state and nationwide class actions and complex commercial litigation encompassing securities and finance, consumer, antitrust, insurance and products. 

Mr. Matt leads the firm's innovation in organizing and prosecuting individual class cases across many states involving the same defendants and similar factual and legal issues; an approach that continues to be a key factor in the firm's success. His prior casework with the firm reflects his diverse experience in most of the firm's practice areas, involving appearances in state and federal courts across the country at both the trial and appellate levels. 

Mr. Matt is a key member of the firm’s securities litigation team, most recently co-leading the prosecution and settlement of the In Re: Charles Schwab Securities Litigation, the In Re: Oppenheimer Champion Income Fund Securities Class Actions, and the Oppenheimer Core Bond Fund Class Action Litigation.

Mr. Matt is also a key member of the firm's pharmaceutical litigation team that confronts unfair and deceptive pricing and marketing practices in the drug and dietary supplement industries. Mr. Matt's cases in this field include the Average Wholesale Price Litigation, the First Databank/McKesson Pricing Fraud Litigation and the Enzyte Litigation. 

Mr. Matt also helps lead the firm's auto defect class action practice and has worked on cases against Toyota, Ford, Nissan, Kia, and Hyundai. 

Other notable cases include In re Checking Account Overdraft Cases pending against many of the country’s largest banks; the Washington State Ferry Litigation, which resulted in one of the most favorable settlements in class litigation in the history of the State of Washington; the Microsoft Consumer Antitrust cases; and State Attorneys General Tobacco Litigation. In the latter, Mr. Matt assisted with client liaison responsibilities, working closely with assistant attorneys general in Oregon, Ohio, Arizona, Alaska and New York, as well as assisting in all litigation matters.

Notable Cases

  • In Re: Charles Schwab Securities Litigation: Settled for $235 Million
  • In Re: Oppenheimer Champion Income Fund Securities Fraud Class Actions: Settled for $52.5 Million (proposed settlement)
  • Oppenheimer Core Bond Fund Class Action Litigation: Settled for $47.5 Million
  • Morrison Knudsen and Costco Wholesale Corp. Securities Litigation
  • In Re: Pharmaceutical Industry Average Wholesale Price Litigation: Settled for $338 million
  • In Re: Toyota Motor Corp. Unintended Acceleration Marketing, Sales Practices, and Products Liability Litigation



  • Providing a Model Responsive to the Needs of Small Businesses at Formation: A Focus on Ex Ante Flexibility and Predictability, 71 Oregon Law Review 631 (1992).

Awards/ Recognition

  • In 2014, Public Justice nominated Mr. Matt and the In re Toyota Motor Corp. Sudden, Unintended Acceleration team as finalists for the prestigious trial lawyer of the year award for their work in securing a $1.6 billion settlement of car owners