The Principal Purpose Test’s Burden of Proof: Should the OECD Commentary on Article 29(9) Specify Which Party Bears the Onus?

Unlike many other provisions of the OECD Model Tax Convention on Income and on Capital (2017), the principal purpose test (PPT) of article 29(9) is new and untested by domestic tax authorities and national courts. Much remains unknown about how the PPT will be implemented in practice, particularly with respect to its burden of proof. Recent academic literature has raised the concern that divergent interpretation and application of the PPT’s burden of proof may either undermine the PPT’s own purpose or unfairly favour one party over the other. This article examines whether these concerns are justified and, if so, whether the Commentary on Article 29(9) should include more prescriptive language with respect to the burden of proof in order to address them.