William Simpson 

Associate – Washington
T.+1 202 862 2214
700 Sixth Street, N.W.
Washington, DC 20001 V-CARD

William Simpson is an associate in the firm’s White Collar Defense and Investigations Group. William’s practice encompasses both civil litigation and criminal proceedings, including representing clients in federal administrative enforcement actions, state and federal courts, and internal investigations. His past experience includes commercial disputes, securities litigation, appellate litigation and administrative law. He also has litigated constitutional issues, including separation of powers challenges to federal agencies and Bivens claims against federal officers, as well as disputes arising under the Controlled Substances Act and federal securities regulations. In those roles, William has advised a variety of clients, including financial services firms, investment funds, large corporations, individual executives and government officials in matters ranging from motions practice and discovery to trial and appellate review.

William received a J.D. from Boston University School of Law, where he was the Executive Articles Editor for the Review of Banking & Financial Law, a legal intern for a state attorney general’s office, and a Symposium Editor for the Harvard Journal of Law & Public Policy. Before law school, William earned a B.S.B.A., cum laude, in Economics and Finance from the University of Arkansas, and worked for several nonprofit and public policy organizations.


  • Comment, The Greek Default and Subsequent Bailout Deal, 35 Rev. Banking & Fin. L. 10 (2015)
  • Note, Above Reproach: How the Consumer Financial Protection Bureau Escapes Constitutional Checks and Balances, 36 Rev. Banking & Fin. L. 343 (2016)
  • Comment, Exit Rights, Pluralism, and Equal Citizenship: Why Religious Exemptions are Still Worth It, 2 J.L. & Pub. Aff. 278 (2017)
  • Co-author, Appraisal Litigation Update, Harv. L. Sch. F. On Corp. Governance and Fin. Reg. (Dec. 27, 2017)
  • Co-author, Five Things Every Company Should Know About Whistleblowers, Bloomberg Law (Aug. 1, 2019)
William Simpson 


  • U.S. Court of Appeals, 2nd Circuit
  • U.S. Court of Appeals, 4th Circuit
  • U.S. Court of Appeals, 5th Circuit
  • U.S. District Court, Southern District of New York
  • District of Columbia
  • New York


  • University of Arkansas
    B.S.B.A., cum laude
  • Boston University School of Law



Our latest podcast covers the legacy of the “Car Wash” investigation and how Brazil fits into the global landscape of white-collar crime enforcement.

To assist individuals in working from home during the coronavirus social-distancing period, Cadwalader is providing clients and friends free access to our legal research platform, the Cadwalader Cabinet.