My Photo


  • Email Address:
  • Website:
  • Location: United States


Mr. O'Brien's practice principally involves litigation and investigations arising out of complex financial transactions, shareholder and partnership disputes, as well as employment disputes. Mr. O’Brien has had significant experience in representing hedge funds, their principals and employees in investigations and litigations.

Mr. O'Brien began his career at Sullivan & Cromwell, LLP, where for one year he litigated his own prisoner civil rights cases as the firm's Pro Bono Fellow. Mr. O'Brien later practiced at Sullivan & Cromwell in the areas of securities and antitrust litigation, and was a member of the trial team in the Department of Justice’s landmark case against Microsoft Corporation. Between 2003 and the founding of O’Brien LLP in 2011, Mr. O’Brien was a partner at a litigation boutique headed by Stanley S. Arkin, one of the nation’s foremost white-collar criminal defense attorneys.

Mr. O'Brien is a contributing author to the Hedge Fund Law Report, and is a lead author of Business Crime, a treatise published by Matthew Bender & Co.