Rebecca Mermelstein is a first-chair trial lawyer with extensive experience handling white collar and finance-related investigations and litigation. She advises corporate and individual clients on complex white collar matters, including regulatory actions, internal investigations, and compliance initiatives.

Prior to joining O’Melveny, Rebecca spent more than a decade as an Assistant U.S. Attorney in the U.S. Attorney’s Office for the Southern District of New York. She was a senior member of the Securities and Commodities Task Force before rising to Co-Chief of the General Crimes Unit. Rebecca has tried 12 cases to verdict, briefed and argued numerous federal appeals, and conducted or supervised more than 1,000 investigations, including grand jury investigations and cross-border matters involving simultaneous investigations by multiple U.S. and international regulators. Her expertise spans securities and accounting fraud, insider trading, Ponzi schemes, money laundering, cybercrime, public corruption, human trafficking, and sexual misconduct.

Through her work leading investigations and prosecutions, Rebecca has established strong working relationships with U.S. Attorney’s Office colleagues and officials at the Securities and Exchange Commission, Commodity Futures Trading Commission, and the Public Company Accounting Oversight Board, as well as federal law enforcement agencies. The knowledge she has gained from her experience and relationships helps her achieve the best possible results for clients.