Katherine A. Trefz

Katherine Trefz Photo

Katie Trefz focuses her practice on criminal defense and government and internal investigations.  She serves as Co-Chair of the firm’s Internal Investigations practice group.  Katie’s work for corporations and senior executives has involved a wide array of substantive allegations, including securities fraud, mail and wire fraud, violations of antitrust law, the Foreign Corrupt Practices Act (FCPA), money laundering, tax fraud, and the False Claims Act (FCA), among others.  Her matters have spanned many industries, including finance, technology, telecommunications, automobile manufacturing, social media, traditional media, law, accounting, food, health care, oil and gas, pharmaceuticals, and professional sports.

Katie also assists clients in complex civil and regulatory matters.  Her civil work currently focuses on defending companies and individuals in matters investigating and alleging potential violations of antitrust law.  Her civil matters have also addressed securities fraud, professional liability, and torts, as well as employment, intellectual property, and commercial disputes.  Katie’s pro bono work has included the representation of criminal defendants and prisoners in federal court. 

Katie has been named a DC Rising Star by the National Law Journal (2022), a Rising Star for white collar criminal defense by Law360 (2020), one of the 500 Leading Litigators in America by Lawdragon (2023-2024), and a member of the “40 & Under Hot List” by Benchmark Litigation (2022).  Katie is a member of the Women’s White Collar Defense Association and the National Association of Criminal Defense Lawyers. She is vice-chair of Williams & Connolly's Hiring Committee.

A native Californian, Katie received her undergraduate degree from the University of Southern California, where she was the Valedictorian of her graduating class, and her law degree from the University of California Berkeley School of Law, from which she graduated Order of the Coif.  She clerked for the Honorable Dean D. Pregerson of the Central District of California before joining the firm in 2009. 

Representative Experience

Though all cases vary and none is predictive, Katie’s criminal defense and investigations experience includes:

  • Served as trial counsel for the former founder and CEO of a biotech company in indicted wire fraud case 
  • Served as trial counsel for a residential mortgage-backed securities (RMBS) trader in federal criminal jury trial alleging securities fraud; all charges dismissed after appeal
  • Defended a telecommunications executive against wire fraud and money laundering charges; prosecution dismissed all charges at trial
  • Represented a multi-national auto-parts supplier in a criminal antitrust investigation
  • Represented a former senior executive of major bank in connection with a Securities and Exchange Commission (SEC) investigation; SEC issued declination letter
  • Defended a bank charged with criminal securities fraud; government settled with a civil resolution on eve of trial




“Washington, D.C. Rising Stars,” The National Law Journal, 2022

“500 Leading Litigators in America,” Lawdragon, 2023-2024

“40 & Under Hot List”, Benchmark Litigation, 2022

Selected to "Rising Stars" list for White Collar Defense, Law360, 2020

Selected to Washington, D.C. “Rising Stars” list, Super Lawyers, 2016-2019


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