This paper will argue that the burden of proof should be on the State invoking the right to deny investment protections under art 17(1). In doing so, s 1 will provide an overview of the questions surrounding ownership and control over investments by a third state under the Energy Charter Treaty (ECT). Section 2 will thereafter initially explore the general theories surrounding burden of proof in international law. Section 3 will then consider ECT art 17(1) and evaluate the nature of the denial-of-benefits provision. Section 4 will analyse the allocation of the burden of proof in establishing ownership and control over an investment under the ECT, after which s 5 will explore the different approaches to allocating the burden of proof under art 17(1). Finally, before concluding, s 6 will analyse which approach of allocating the burden of proof under art 17(1) might be better suited with regard to the objectives and spirit of the ECT.