FacultyFaculty/Author Profile

Douglas W. Mateyaschuk

DLA Piper LLP (US)

New York, NY, USA

Douglas W. Mateyaschuk II is currently an associate at DLA Piper.  Prior to joining, he was a senior associate with Dewey & LeBoeuf LLP. He specializes in complex commercial litigation, mass tort defense, and international law. He has spent the last eight years defending various financial institutions in connection with novel multi-billion dollar claims filed under the Alien Tort Statute and Anti-Terrorism Act.    


Mr. Mateyaschuk specializes in complex commercial litigation, mass tort defense, and international law. He has litigated precedent-setting cases in state, district and appellate courts, including serving as co-counsel for amicus parties in the Supreme Court of the United States. Mr. Mateyaschuk is known for developing unique solutions to complex litigation problems, and has authored numerous motions on novel legal issues. He has represented clients in the financial, telecommunications, consumer products, and investment industries, as well as several high net worth individuals in personal litigation.

Mr. Mateyaschuk's representative matters include:

  • Defending international banks against claims seeking billions of dollars in damages under the Anti-Terrorism Act and Alien Tort Statute;
  • Achieving the precedent-setting dismissal of claims seeking hundreds of millions of dollars in damages against an international financial institution pursuant to a previously untested provision of the Anti-Terrorism Act;
  • Participating in the successful defense of a Lebanese-based financial institution against claims seeking hundreds of millions of dollars in damages arising from injuries suffered as a result of cross-border conflict;
  • Leading a global investigation into an alleged fraud on the part of participants to a synthetic letter of credit and coordinating the related efforts of staff in Ireland, England, China, Spain and Bahrain;
  • Representing financial institutions in connection with investigations by the Department of the Treasury and the Department of Justice relating to alleged Bank Secrecy Act and OFAC compliance deficiencies;
  • Successfully arguing a heavily contested motion to compel the production of foreign documents in a breach of contract and fraud action before the Supreme Court of the State of New York;
  • Representing a national retailer of men's grooming products in a trade dress infringement matter that resulted in a pre-litigation favorable resolution for the firm's client;
  • Representing a high-net worth individual in an extortion and harassment case, and having vexatious Web content removed from servers maintained by U.S.-based Web hosts through negotiations and proceedings before the District Court for the District of Connecticut;
  • Defending several U.S. corporations in a contested compensation case filed by a former executive; and
  • Obtaining the removal and retraction of defamatory news articles residing on a Russian server and published on the Web by a popular news site in Israel.

Mr. Mateyaschuk has served as a judge for the 2007 and 2011 Constance Baker Motley National Moot Court Competitions in Constitutional Law. He is also the co-author of the firm's publication Credit in Crisis: An Analysis of Credit Rating Agency Exposure to Sup-prime Claims.
Prior to joining Dewey & LeBoeuf, Mr. Mateyaschuk worked on Capitol Hill for Senator Charles E. Schumer. He is also a long distance runner and has run races to raise money for charities, including the Organization for Autism Research.

Selected Activities

  • American Constitution Society


  • Georgetown University Law Center, 2004, J.D.
  • Hofstra University, 2000, B.A., summa cum laude, High Honors, Phi Beta Kappa, Pi Sigma Alpha, Rosenbaum Prize for Outstanding Writing

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