It is our mission to support governments, tax administrations, taxpayers, advisors and lawyers with highest quality international tax expertise that is clear, thorough and independent. We provide services both independently as well as collectively in international tax cases and in arbitration proceedings.


Danon, Douma & Kofler was founded as a network by Professors Robert Danon from Switzerland, Sjoerd Douma from the Netherlands, and Georg Kofler from Austria. Next to our academic activities, we have significant experience in private practice and the judiciary in Switzerland, the Netherlands, and Austria, respectively.

Our specializations include tax treaty law (including its relation with investment law), public international law, tax policy, all fields of European Union (EU) primary and secondary tax law (including fundamental freedoms, State aid, EU directives, such as the anti-tax avoidance directives), international tax, commercial and investment law arbitration, as well as business and individual taxation in general in Switzerland, the Netherlands, and Austria. We have vast academic and practical experience in those fields, with past work including expert witness reports for courts, scientific support in litigation and negotiation, and international arbitration.

What we do

We do not provide classical prospective tax advice but rather focus on expert opinions, conflict resolution and expert counsel services in the context of disputes, transactions or restructurings, domestic and international alike. We assist both governments and/or tax administrations, and taxpayers and/or their representatives.

In particular, and in compliance with domestic regulations, we provide the following services:

  • Giving evidence as a testifying expert in arbitration proceedings including those involving non-tax agreements, such as bilateral investment treaties (BITs)
  • Serving as arbitrators in international tax, commercial or investment arbitrations
  • Providing support or acting as a consultant in tax treaty and EU mutual agreement proceedings as well as commercial and investment law arbitration; we are in particular able to assist with disputes based on tax treaties, the multilateral instrument (MLI), the EU arbitration convention, the EU dispute resolution directive or on non-tax agreements (such as BITS)
  • The provision of expert opinions or reports in court litigation
  • The provision of tax opinions in the context of the annual audit cycle of a company
  • Assistance in the context of joint or simultaneous audits
  • Acting as expert counsel in the context of transactions, deals and restructurings
  • The provision of a second opinion on advice provided by tax advisors or lawyers
  • Estimation of the chance of success in the event of litigation


Independence is a cornerstone of Danon, Douma & Kofler. We provide our independent scientific views and services based on our established academic knowledge and practical experience. We remain fully independent from each other and are instructed separately. Depending on the subject matter of the assignment, we may however act jointly, providing our expertise in a coordinated and complementary way. Any previous association with potential clients or other conflicts of interest are thoroughly reviewed and addressed prior to the commencement of an assignment.