Does customary international law exist in tax? There are over 3,000 bilateral tax treaties, and they are about 80% identical to each other, but do they create customary international law that binds in the absence of a binding treaty, like, for example, the Vienna Convention on the Law of Treaties binds the United States, which has not ratified it? This Chapter will argue that the answer is yes, using four examples: jurisdiction to tax, the permanent establishment threshold, the arm’s length standard, and non-discrimination.
"Does Customary International Tax Law Exist?"
Research Handbook on International Taxation