The treatment of tax in investor-state arbitration of expropriation and national treatment protection

Abstract

This thesis examines the treatment of tax in investor-state arbitration of expropriation and national treatment protection. The root of the study is the special characterisation of tax in the sovereignty of the state and the consequent sensitivity of states to have their tax policies being the subject of private adjudication. Tax has in the past been characterised as a non-arbitrable matter, but that is true only if states have purposefully deemed them so under the international investment treaties that they are party to. Tax is generally arbitrable under the expropriation provisions of international investment treaties, but states are seldom found liable for tax expropriation. National treatment, on the other hand, is generally not arbitrable under international investment treaties, but when an investment treaty permits the arbitration of alleged national treatment tax violations, violations are affirmed in more cases than not. The reason behind the comparable success rates is the difficulty in proving the existence of expropriation by taxation whereas national treatment tax violations are comparatively easier to substantiate. This thesis establishes what constitutes a tax expropriation, and how the success rate of claims for national treatment tax violations justifies the general exclusion of the application of national treatment protection to tax matters for sovereignty retention. In order to achieve the foregoing, this thesis examines sovereignty and the sovereign power to tax; the relinquishment of tax sovereignty under international investment treaties; the arbitrability of tax and the reasoning behind the reluctance of states to submit tax disputes to arbitration; the capability of tax to be expropriatory; the fundamentals of the expropriation standard under customary international law and international investment treaties and how they are applied by arbitral tribunals in tax expropriation claims; and the fundamentals of the national treatment protection and how they are applied by arbitral tribunals in claims for national treatment tax violations.