James Warren is a Partner in the firm’s Tax practice group.  Formerly a banker in London, New York and Germany, Mr. Warren has focused his legal practice on federal income tax matters, international restructurings and cross-border transactions.  He has long experience handling tax controversies, having represented Freddie Mac for many years in a series of reported cases in the U.S. Tax Court, and advising clients on domestic and international tax planning and compliance.

In addition to his tax practice, Mr. Warren has wide experience in a variety of humanitarian and philanthropic matters, including serving as independent trial observer in a political trial in Ethiopia, assisting the prosecution in the International Criminal Tribunal for Rwanda in Tanzania and conducting trial advocacy training in Liberia. He is advisor to, or a board member of, a variety of nonprofits, many of which he helped to establish.

Representative Experience

  • Advised major corporations on international and corporate tax planning and transactions, structuring of in-bound and out-bound investments, subpart F., foreign tax credits, etc.
  • Advised banks and financial institutions on federal taxation of financial products and derivatives.
  • Handled tax litigation and controversies for corporations, financial institutions and individuals with the IRS Appeals Division and before the U.S. Tax Court.
  • Counsel to the board of various tax-exempt organizations involved in education, healthcare and the promotion of civil society in foreign countries, particularly in Jordan and neighboring countries in the Middle East.

Publications and Speeches

  • Risks, Reading Corporate Signals (John Wiley, 1987), Co-Author

Civic Involvement

  • Officer, Order of St. John of Jerusalem
  • Representation of the School for Ethics and Global Leadership, Washington, DC

Memberships and Affiliations

  • Cosmos Club


  • Arabic
  • French
  • Italian


Harvard Law School, J.D.

  • magna cum laude

Cambridge University, M.A. and B.A. 

  • First Class Honors in Classics and Middle Eastern Languages

Previous Experience

  • Shearman & Sterling, LLP, Tax Counsel


  • District of Columbia
  • U.S District Court for the District of Columbia
  • U.S District Court for the Eastern District of North Carolina
  • U.S District Court for the Central District of North Carolina
  • U.S District Court for the Western District of North Carolina
  • U.S. Tax Court
  • U.K. Solicitor

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