William Simpson 

Associate – New York
T.+1 202 862 2214
200 Liberty Street
New York, NY 10281 V-CARD

William Simpson is an associate in the firm’s Global Litigation Group and an experienced litigator in both civil and criminal proceedings. His practice includes commercial disputes, securities litigation, appellate litigation, and white collar defense matters in state and federal courts, federal administrative enforcement actions, and internal investigations. From motions practice and discovery to trial and appellate review, William has represented financial services firms, investment funds, large corporations, individual executives, and government officials. He was named a Rising Star by Super Lawyers in 2022.

His complex commercial litigation experience includes cases concerning structured financial products and bondholder disputes, shareholder litigation, and contract disputes. He has also 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 a member of the firm’s White Collar Defense and Investigations Practice, he frequently defends clients facing government enforcement actions and investigations, including issues arising under the Controlled Substances Act and federal securities regulations. That practice emphasizes administrative law issues, including defending against agency enforcement actions or challenging them in court, responding to agency rulemaking, and all facets of the Administrative Procedure Act. In other recent white collar matters, he has represented both relators and defendants in False Claims Act cases, and represented individuals from indictment to sentencing in wire fraud, health care fraud, and other financial crimes cases.

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.

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