Overview
(June 1, 2026, San Francisco) – Steptoe LLP announced today that Mario Nguyen, a skilled litigator, legal technologist, and former federal prosecutor with extensive experience in cross-border investigations, compliance counseling, and complex fraud litigation, has joined the firm's Investigations, White-Collar, and Compliance Group in San Francisco.
Mario brings exceptional experience from all sides of the courtroom, having served as a federal prosecutor, a criminal defense lawyer, and a federal judicial law clerk. As a Trial Attorney in the Fraud Section of the US Department of Justice's Criminal Division, Mario supported some of the nation's most complex fraud investigations and prosecutions, including work with Task Force KleptoCapture, a multi-agency initiative enforcing economic sanctions and export controls imposed in response to Russia's invasion of Ukraine.
Mario also served as an inaugural law clerk to a newly appointed federal district court judge in California's Southern District, which encompasses the second most populous county in the state. In private practice, Mario has advised clients at both a major international law firm and an elite boutique law firm on complex white-collar matters, investigations, and compliance issues.
At Steptoe, Mario's practice will focus on complex criminal and civil enforcement actions, internal and government investigations, and compliance counseling for clients across industries, including technology companies, governmental agencies, multinational corporations, start-ups, nonprofits, as well as celebrities and corporate executives. He will also advise clients on AI governance frameworks, and help clients modernize their litigation strategy, investigations capabilities, and compliance programs through responsible use of artificial intelligence. Fluent in Spanish and a former Fulbright Scholar to Mexico, Mario is particularly experienced in cross-border matters involving Latin America.
"With increased enforcement targeting emerging technologies, I am thrilled to join Steptoe and help expand its investigations, compliance, and litigation capabilities in the Bay Area," said Nguyen. "The firm's global platform, commitment to legal innovation, and highly regarded Investigations, White-Collar, and Compliance Group offer the ideal environment to help clients navigate enforcement actions and build AI-driven compliance programs that prevent misconduct before it occurs."
About Steptoe
In more than 110 years of practice, Steptoe has earned an international reputation for vigorous representation of clients and innovative thinking before governmental agencies, successful advocacy in litigation and arbitration, and creative and practical advice in structuring business transactions. Steptoe has more than 500 lawyers and other professional staff across offices in Beijing, Brussels, Chicago, Hong Kong, Houston, London, Los Angeles, New York, San Francisco, and Washington, DC. For more information, visit www.steptoe.com.
