Tax and Investment Treaty Overlaps

PhD thesis

Written by: Carina Frahm

Supervisors: Dr Esperanza Buitrago Díaz (on behalf of the University of Rosario) and Prof Dr Raymond Luja

Keywords: Double Taxation Conventions, International Investment Agreements, Fragmentation of International Law, Depoliticization

Every euro of foreign investment is fought over, and companies demand certainty before they commit. Yet the treaties governing international tax and foreign investment are becoming a tangled mess to operate as two completely separate worlds. This legal fragmentation doesn’t just confuse businesses – it creates opportunities for governments to overstep. The result? A paradox: states try to fund growth while discouraging the very investment they depend on. Instead of bridging the gap, UN proposals – pushed by tax authorities – threaten to pull these two systems even further apart, leaving businesses trapped in the crossfire. 

The UN’s newest framework suggests that investment arbitration should play no role in matters covered by bilateral tax treaties. This PhD reaches the opposite conclusion: as politics should be kept out of judicial review and legal protection, arbitrary, discriminative or confiscatory tax treatment might still call for independent review.

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