Brian O'Neill is the Managing Partner of the law firm O'Neill & Partners LLC.  Brian counsels clients on a wide range of legal, regulatory and compliance matters.  Brian's practice focuses on broker-dealer and exchange regulatory compliance issues and advising companies on matters related to compliance with SEC and self-regulatory organization (SRO) regulations.  In addition, Brian provides outside general counsel services to foreign and domestic entities in the financial services, energy, construction, hospitality, medical and health services, agriculture, and technology industries.  As part of his general counsel services, he advises companies on corporate formation, employment documentation, IP strategy, real estate, contract drafting, and capital raising.


Brian spent most of his legal career at regulators and SROs, including time at the SEC, FINRA, CFTC, NYSE Euronext, MIAX Options Exchange, and the state regulator DISB.  Over the course of his regulatory career, Brian has reviewed and/or drafted over 500 rules and corresponding 19b-4 rule filings for equity and options exchanges and worked on 5 new exchange registrations.  He managed the legal department and drafted a Form 1 exchange registration for a new equities exchange, drafted comment letters, policies/procedures, and responses to regulatory inquiries.  In addition, Brian participated in industry-wide committees where he drafted model rules used by exchanges.  Prior to private practice, Brian served as an executive director and compliance director at a large financial institution where he managed an international team with responsibilities in APAC, EMEA, LATAM, and North America.


Prior to his legal career, Brian was member of the Chicago Board of Trade, where he traded futures as a floor trader.  He was also a Sergeant in the United States Marine Corps, where he served as a heavy machine-gunner and Embassy Guard in Switzerland and Bangladesh. 


  • Georgetown University, Walsh School of Foreign Service, B.S. Finance

  • The University of Pennsylvania, M.S.Ed.

  • American University, Washington College of Law, J.D.


  • District of Columbia

  • Maryland