Sean M. Thornton



Financial Institutions Regulation and Enforcement
Economic Sanctions and Anti-Money Laundering

Washington, D.C.

T: 1.202.371.7149

F: 1.202.661.9149


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Sean M. Thornton served from 2005 to 2012 as chief counsel of the U.S. Department of the Treasury’s Office of Foreign Assets Control (OFAC), where he helped develop and implement the expanding legal framework for U.S. economic sanctions with respect to Iran and played a leading role in a series of landmark settlements with international banks for alleged violations of U.S. sanctions. Mr. Thornton also has advised senior officials in the Department of the Treasury, Department of Justice, Department of State and the White House in a wide range of other financial enforcement and regulatory matters, including anti-money laundering (AML), national security litigation and issues relating to the Committee on Foreign Investment in the United States.

Mr. Thornton’s practice focuses on the shifting laws and policies underlying U.S. economic sanctions, as well as AML best practices and requirements. His experience includes:

  • Representing clients in economic sanctions cases, including conducting internal reviews and negotiations with the Department of the Treasury, Department of Justice and New York authorities.
  • Advising clients on economic sanctions issues in high-profile cross-border transactions.
  • Conducting assessments of clients’ compliance programs, including an intensive on-site AML review of the foreign-exchange business of a large Latin American bank.
  • Securing licenses and other regulatory action when needed.
  • Representing companies and individuals that have been sanctioned by U.S. authorities, helping the clients identify and address the reasons for the sanctions, and advocating on their behalf before relevant U.S. agencies.

Speaking Engagements

  • French Ministry of Foreign Affairs, “La justice négociée américaine, un nouvel enjeu économique et stratégique,” December 2013
  • Asia Summit on Economic Sanctions (American Conference Institute), “Iran — How to Comply with Tighter U.S. Sanctions,” December 2013
  • British Bankers’ Association Sanctions Conference, “Horizon Scanning — The Direction of U.S. Regulatory Enforcement,” November 2013
  • Wilton Park (Sussex, U.K.), “Meeting the Emerging Challenge of Illicit Nuclear Procurement,” September 2013
  • Co-Chair, International Congress on Economic Sanctions and Anti-Money Laundering (Momentum), June 2013
  • Advanced Forum on Economic Sanctions Compliance & Enforcement (American Conference Institute),“Sanctions Against Syria: Past, Present, and Predictions,” June 2013
  • Georgetown University Law Center, Georgetown Journal of International Law Symposium, “The Evolution of Economic Sanctions,” February 2013
  • Institute on Securities Regulation in Europe (Practising Law Institute), “Sanctions Issues in Governance and Deal-Making: How to Survive,” January 2013
  • OFAC Boot Camp (American Conference Institute), “What to Do if You Suspect or Discover a U.S. Sanctions Violation: How to Structure an Internal Investigation to Mitigate Liability Risks and Implement Effective Remedial Measures,” December 2012

Bar Admissions

District of Columbia


J.D., Georgetown University Law Center, 1997 (cum laude)

A.B., Harvard College, 1994 (magna cum laude)

Government Service

U.S. Department of the Treasury: Chief Counsel, Office of Foreign Assets Control (2005-2012), Senior Adviser to the General Counsel (2003-2005), Attorney Adviser, Office of the General Counsel (2001-2003)

Law Clerk, District of Columbia Court of Appeals, Hon. John M. Steadman (1997-1998)