Sidne Koenigsberg focuses on cross-border litigation, compliance and enforcement matters for financial institutions. She has worked with major international banks on internal investigations related to U.S. anti-money laundering and economic sanctions laws.


Ms. Koenigsberg also assisted in the successful defense of an international financial institution and several of its senior executives in a U.S. class action securities litigation. She has experience advising international clients on banking secrecy and data protection matters under French law in the context of U.S. litigation and internal investigations.

Ms. Koenigsberg also has assisted on general corporate matters for private and public companies including mergers and acquisitions, financing and U.S. securities offerings.

In addition, Ms. Koenigsberg frequently advises not-for-profit corporations, non-governmental organizations and artists in a variety of pro bono matters.

As a Dean Acheson Legal Scholar, Ms. Koenigsberg served as a clerk for Judge Allan Rosas, president of the Third Chamber of the Court of Justice of the European Communities.



  • J.D., Columbia University School of Law, 2006 (Symposium Editor, Columbia Journal of Law and the Arts; Harlan Fiske Stone Scholar)
  • B.A., Amherst College, 2003 (magna cum laude; Phi Beta Kappa)


  • New York
  • Paris


  • English
  • French

Sidne Koenigsberg

Counsel, Financial Institutions Regulation and Enforcement