References to the OECD Commentaries in Tax Treaties: A Steady March from “Soft” Law to “Hard” Law?

This article addresses, in part, the use of the OECD Commentaries with respect to the interpretation of bilateral tax treaties. However, the article has as its focus those instances in which a tax treaty or protocol to a tax treaty, in the main, directly reference the OECD Commentaries as an interpretational rule. Such direct references to the OECD Commentaries spark a number of questions and reopen issues such as the hard law/soft law dichotomy; the static versus ambulatory nature of the OECD Commentaries; policy reasons for such inclusions and the consequences of such inclusions. This article equally provides the base from which the rise of such references can be monitored. The article collects and analyses the direct references, stratifying these “rules” into types while looking for trends. While the number of instances remains low relative to the total number of bilateral comprehensive tax treaties worldwide, the inclusions of such rules equally open the debate regarding the formation of customary international law. Currently, these rules may simply achieve the aim for which they appear to have been created, being the affirmation that the parties consider the OECD Commentaries as a key interpretational resource and, although still to be tested, to force the courts to actively consider the rules in making judgments in tax treaty matters.