Arbitration and the United Nations Framework Convention on Tax

The document examines the risks of incorporating arbitration, specifically investor-state dispute settlement (ISDS), into the UN Framework Convention on International Tax Cooperation (UN FCITC). It contrasts ISDS with mandatory binding arbitration (MBA) and the mutual agreement procedure (MAP), highlighting structural flaws in ISDS such as high costs, inconsistent decision-making, and 'regulatory chill'. Drawing on the prolonged reform efforts of UNCITRAL Working Group III, the brief warns that adopting complex arbitration mechanisms can lead to institutional lock-in and asymmetric influence in negotiations. It recommends that the UN FCITC include safeguards, such as carve-out clauses, to protect fiscal sovereignty and discourage the use of ISDS for tax disputes.

• Tax-related ISDS cases have increased significantly, with 114 cases initiated between 2010 and 2021 compared to only 51 before 2009. These claims predominantly involve investors from North America and Western Europe against states in South America, Eastern Europe, and Central Asia.
• ISDS presents severe financial risks to states due to high legal costs and massive compensation awards. Average legal costs for states are around USD 4.7 million per case, and the average damages award between 2014 and 2023 was approximately USD 256 million.
• The ISDS system is characterized by inconsistent and unpredictable decision-making because it lacks a binding doctrine of precedent. This leads to divergent interpretations of whether tax measures constitute indirect expropriation, which can create a 'regulatory chill' where states refrain from policy actions to avoid expensive litigation.
• Mandatory binding arbitration (MBA) in tax treaties differs from ISDS in that it is a state-to-state mechanism where implementation occurs through tax authorities rather than through binding, judicially enforceable awards that allow private investors direct standing.
• The experience of UNCITRAL Working Group III (WG III) serves as a warning for the UN FCITC, demonstrating that reforming international arbitration is resource-intensive and prone to 'institutional lock-in'. WG III has spent over seven years without reaching a definitive agreement on how to operationalize reforms.
• The brief proposes that the UN FCITC should actively discourage ISDS for tax disputes, potentially by using a carve-out clause similar to the 2025 UN Model Tax Treaty, which specifies that measures implemented under the Convention do not breach other treaties.

APA

Lago, J. D. R., Readhead, A., Mataba, K., & Ostřanský, J. (2026). Arbitration and the United Nations Framework Convention on Tax. International Institute for Sustainable Development. https://www.iisd.org/system/files/2026-01/un-tax-convention-arbitration-isds.pdf

Chicago

Lago, Josefina del Rosario, Alexandra Readhead, Kudzai Mataba, and Josef Ostřanský. Arbitration and the United Nations Framework Convention on Tax. International Institute for Sustainable Development, 2026. https://www.iisd.org/system/files/2026-01/un-tax-convention-arbitration-isds.pdf.

Wikipedia

{{cite report |last1=Lago |first1=Josefina del Rosario |last2=Readhead |first2=Alexandra |last3=Mataba |first3=Kudzai |last4=Ostřanský |first4=Josef |title=Arbitration and the United Nations Framework Convention on Tax |publisher=International Institute for Sustainable Development |date=January 2026 |url=https://www.iisd.org/system/files/2026-01/un-tax-convention-arbitration-isds.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{lago2026arbitration, author = {Lago, Josefina del Rosario and Readhead, Alexandra and Mataba, Kudzai and Ostřanský, Josef}, title = {{Arbitration and the United Nations Framework Convention on Tax}}, institution = {International Institute for Sustainable Development}, year = {2026}, month = jan, url = {https://www.iisd.org/system/files/2026-01/un-tax-convention-arbitration-isds.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }