Rob Barthelmess


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Rob Barthelmess is a litigation associate in O’Melveny’s Los Angeles office, where he devotes much of his practice to white collar criminal defense and corporate investigations, complex civil litigation, and regulatory matters. Before returning to O’Melveny in 2019, Rob served as a law clerk to the Honorable Ryan D. Nelson in the United States Court of Appeals for the Ninth Circuit.

Rob graduated cum laude from the Georgetown University Law Center. While in law school, Rob worked as a law clerk at the United States Senate Committee on the Judiciary, Subcommittee on Antitrust, Competition Policy and Consumer Rights, the United States Securities & Exchange Commission’s Division of Enforcement, and the Santa Barbara County District Attorney’s Office.


Bar Admissions

  • California

Court Admissions

  • US District Court, Central District of California
  • US Court of Appeals, Ninth Circuit


  • Georgetown University, J.D.: cum laude; Dean’s List;  Executive Notes Editor, Journal of National Security Law & Policy
  • University of California at Los Angeles, B.A., Philosophy

Professional Activities


  • United States Senate Committee on the Judiciary, Subcommittee on Antitrust, Competition Policy and Consumer Rights, Office of Senator Mike Lee, Chairman
  • United States Securities & Exchange Commission, Division of Enforcement


  • Honorable Ryan D. Nelson, United States Court of Appeals for the Ninth Circuit
  • Representing multinational companies and individuals in fraud litigation in California state and federal courts.
  • Conducting internal investigations on behalf of a managed care organization in connection with investigations by the Department of Justice.
  • Defending an electric-vehicle and technology company in an Alien Tort Statute action.
  • Advising a financial institution on appellate strategy.
  • Representing individuals in connection with SEC and DOJ investigations.