Revisiting the case of customary international tax law

Abstract

Customary international tax law has traditionally not received a lot of acclaim in international tax law literature. However, the infrastructure of international tax law is becoming increasingly multilateral. The recent adoption of the Multilateral Instrument and the creation of the Inclusive Framework, two initiatives related to the OECD/G20 Base Erosion and Profit Shifting Project, have accelerated the width of cooperation on international tax matters. For that reason, the authors (re)consider the existence of customary international law in the area of international tax law. They conclude that, perhaps contrary to the intuition of tax lawyers, the evidence in favour of customary international tax law is building up. The question whether customary law exists within the area of international taxation is therefore not misplaced.