Tax Arbitrage and the International Tax Regime

It is a great pleasure to introduce my student Luca Dell\u27Anese\u27s book on tax arbitrage. This is an important book on an important topic, which lies at the heart of the current debate on whether an international tax regime exists in practice. I have argued for many years (see, e.g., Avi-Yonah, 1996, 1997, 2000) that a coherent international tax regime exists, embodied in both the tax treaty network and in domestic laws, and that it forms a significant part of international law (both treatybased and customary). The practical implication is that countries are not free to adopt any international tax rules they please, but rather operate in the context of the regime, which changes in the same ways international law changes over time. Thus, unilateral action is possible, but is also restricted, and countries are generally reluctant to take unilateral actions that violate the basic norms that underlie the regime. Those norms are the single tax principle (i.e., that income should be taxed once- not more and not less) and the benefits principle (i.e., that active business income should be taxed primarily at source, and passive investment income primarily at residence)