Johannes Willheim

International Mediators

Johannes Willheim’s practice focuses on international arbitration and business litigation. He acts as party advisor prior to, during, and post-formal proceedings as well as legal representative in formal proceedings. Johannes is also frequently appointed as an arbitrator, mediator, and independent expert in ICC, VIAC, and other institutional as well as ad hoc proceedings. His case docket is comprised of antitrust, corporate and post-transaction, energy, engineering and construction, distribution, insurance, IP, and regulatory disputes. The majority of the cases he handles are high-stake, many of which have been successfully decided at the Supreme Court level and have become milestones cases.

Johannes coordinates the Firm’s Austrian law desk, which provides a broad range of Austrian corporate, commercial, and regulatory services, in particular in the area of M&A and financial services transactions. Johannes and his Austrian law qualified team members regularly represent Firm clients before Austrian courts and governmental authorities.

Johannes is currently handling major gas price revision disputes in Europe for one of the world’s leading producers of natural gas. He has become an authority in arbitrating cases involving EU competition law issues and in litigating antitrust cases before national courts either on the defense side or on the enforcement side.

Johannes is a frequent speaker at arbitration, antitrust, and energy conferences and is author of publications on these subjects.


Representation of Pöyry Energy in litigation against OMV Exploration & Production under an EPCM contract for the design and construction of a water treatment plant used for oil production

Representation of Euromicron in ICDR arbitration against 4D Solutions arising under a sub-contract for the design and implementation of a defense security system for the US Army in Wiesbaden, Germany

Sole Arbitrator in proceedings under the Arbitration Rules of the German Arbitration Center relating to a wind park project

Representation of Gazprom Export in price revision arbitrations under ICC and other arbitration rules

Representation of IF (Finnish insurance company) in dispute against VA Tech under a professional insurance policy


  • ICC Commission on Arbitration and Dispute Resolution
  • ICC Commission on Competition
  • Austrian Arbitration Association (ArbAut)
  • Dutch Arbitration Association (DAA)
  • German Arbitration Association (DIS)
  • Swiss Arbitration Association (ASA)


German, English, French


The University of Chicago (LL.M. 2004); King’s College London (Postgraduate Diploma in EC Competition Law 2003); University of Vienna (Dr. iur. 2002; Mag. iur. 1997); University of St. Gallen (Master of European and International Business Law 2001); Yale University (Summer programs in Business and Law, 1991 and 1992)

Bar Admissions

Austrian Bar and registered European attorney with the Frankfurt Bar