William Simpson 

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

William Simpson is an associate in the firm’s White Collar Defense and Investigations Group. He represents clients in both civil litigation and criminal proceedings, including state and federal courts, federal administrative enforcement actions, and internal investigations. His practice emphasizes administrative law, including defending against agency enforcement actions or challenging them in court, responding to agency rulemaking, and all facets of the Administrative Procedure Act.

William’s experience also includes commercial disputes, securities litigation, and appellate litigation. He has litigated a number of constitutional issues, including separation of powers challenges to federal agencies, First Amendment free speech claims against state and federal regulations, and civil rights 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)
  • Co-author, Supreme Court Ruling Does Not End the Fight Over the CFPB, Bloomberg Law (July 30, 2020)
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


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