Thomas Obersteiner practices in the Litigation Department. He focuses on all issues of U.S. and E.U. antitrust law, including mergers and acquisitions, antitrust investigations and antitrust litigation. His experience includes representing clients in complex international arbitration cases, in particular investors in investor-state disputes.


Prior to joining Willkie, Thomas was an associate with Baker & McKenzie (2012-2018), where he gained experience in international dispute settlement and E.U. competition law. Thomas also served as a trainee for the E.U. Commission’s Directorate-General for Competition (2011) and the Appellate Body Secretariat of the World Trade Organization (2012).

Thomas is a member of the American Bar Association (Antitrust Section) and the New York State Bar Association.

While at Columbia Law School, Thomas served as a Graduate Editor of the American Review of International Arbitration; and as a board member for the Columbia Antitrust Law and Economics Association (CALEA).

  • Private Antitrust Enforcement in the U.S. and the E.U. – A Comparison of Key Issues, Corporate Counsel Review (State Bar of Texas), publication expected in mid-2020.
  • Provisional Measures under ICSID Rules – The Power of Tribunal to Interfere with Domestic Criminal Proceedings, Journal of International Arbitration (Wolters Kluwer), publication expected in mid-2020  .
  • “In Accordance with Domestic Law” Clauses: How International Investment Tribunals Deal with Allegations of Unlawful Conduct of Investors, Journal of International Arbitration (Wolters Kluwer) 31, no. 2 (2014): 265–288.
  • International Antitrust Litigation: How to Manage Multijurisdictional Leniency Applications, Journal of European Competition Law and Practice (Oxford), Vol 4 Issue 1, 2013, pp. 16-31.
  • The Scope of the TBT Agreement in Light of Recent WTO Case Law, Global Trade and Customs Journal, Issue 4, 2013, pp. 112–120 (with Luciana D.O. Silveira)



Columbia Law School, LLM, 2019 University of Barcelona, LLM, 2011 University of Vienna, J.D., 2009 Vienna University of Economics and Business, BBA, 2009

Bar Admissions

Austria, 2015


Takacs-Aust, Zeilinger and Sperl, Vienna Higher Regional Court, 5/2009 - 7/2010