Skip to main content

William Briendel is Co-Chair of the Broker-Dealer Securities Litigation Practice and a litigator who represents broker-dealers and their employees in virtually all aspects of their business. He is experienced in arbitrations and mediations before the Financial Industry Regulatory Authority (FINRA) (which combined the arbitration and enforcement functions of the National Association of Securities Dealers (NASD) and the New York Stock Exchange (NYSE)) and the American Arbitration Association (AAA), and in regulatory and enforcement proceedings before the Securities and Exchange Commission (SEC), FINRA and other regulatory and self-regulatory organizations. Bill also conducts internal investigations for his broker-dealer clients. He has a wide-ranging experience in a broad range of commercial litigation matters as well.


  • Securities/Broker-Dealer arbitration and mediation
  • Securities/Broker-Dealer regulatory practice
  • Internal investigations
  • Broker-Dealer employment matters
  • Complex civil litigation



  • Represented executives of Broker-Dealer in multiple SEC investigations in connection with the sale of various products.
  • Represented numerous NASDAQ traders in SEC investigation into alleged price fixing and manipulation by NASDAQ market makers.
  • Represented numerous public companies in connection with SEC investigations into revenue recognition and alleged inflated earnings reports.
  • Represented numerous brokers in NASD and NYSE arbitrations in both customer and "raiding" cases.
  • Represented various individuals in SEC investigations involving insider trading, market manipulation and other alleged securities law violations.
  • Represented numerous branch managers in failure to supervise investigations and/or actions commenced by the NYSE and NASD.
  • Represented numerous brokers in enforcement proceedings commenced by the SEC, NYSE, NASD and CBOE.

Recognition & Leadership

  • Listed, The Legal 500 United States
    • Dispute Resolution - Securities Litigation - Defense, 2017-2023
    • Litigation - Securities - Shareholder Litigation, 2014-2016
  • Member, New York State Bar Association
  • Past President, Variety The Children's Charity
  • Volunteer, Memorial Sloan Kettering Cancer Center: Pediatric Unit


  • J.D., cum laude, Georgetown University Law Center, 1984
    • Associate editor, The Tax Lawyer
  • B.A., cum laude, University of Massachusetts at Amherst, 1981
  • New York