Customary International Law and Tax Jurisdiction

Customary International Law and Tax Jurisdiction is a book portraying the most exhaustive and robust empirical analysis of customary international tax law to date. Little attention has been paid to the pervasive effects of customary international law in contemporary issues of international taxation. Customary international law influences states’ bargaining power in treaty negotiations, serves as a gap-filler for issues not regulated by treaties, and informs the interpretation of tax treaties by judges and administrative agencies.

Employing a novel and carefully theorized methodology for the identification of customary international law concerning international tax law, the author approaches the subject through an assessment of three crucial jurisdictional issues:

• the nexus principle, which specifies how a state must be connected to a subject or object to exercise tax jurisdiction;
• the norms that govern the cross-border taxation of corporate business profits; and
• the nexus of ownership and control and, by extension, the role of the corporate veil in contemporary international tax law.

A central contribution of this book is its new data set that compares the relevant practices of 80 states, providing a much larger and more geographically representative sample than any previous study. Additionally, the book comprises a comprehensive discussion on how customary limits to tax jurisdiction relate to current reform proposals spearheaded by the OECD/G20 Inclusive Framework and by the UN General Assembly, as well as unilateral measures such as digital services taxes; it thereby offers new insights to the debate on their conformity or divergence from the normative status quo of international tax law.

In essence, this book strives to encourage intra-disciplinary dialogue between international tax lawyers and public international lawyers by furnishing an accessible analysis of a complex interaction – a feature that will benefit academics and policymakers in both fields.