This article is the first to address the use of trusts in investment arbitration, and particularly all those instances in which trust structures may have a direct bearing on investment treaty claims. As a matter of fact, the increasing use of trusts in transnational business has created a whole new set of considerations that call for the attention of users and practitioners alike. Owing to the intricacies of trusts, and in the light of a series of recent cases, this article sets out to explore such questions as standing to sue, authorisation to bring claims on behalf of the trust or the assets held in trust, whether the trustee, the beneficiary or other trust parties should be considered covered investors, whether the trust itself may have standing, whether any resulting damages award should form part of the trust assets and be distributed in accordance with the trust deed as well as other admissibility and quantum-related questions that may arise when dealing with trusts. All in all, this article maps the multitude of issues that trust structures raise in investment arbitration. And while it may be too early to draw any conclusive remarks based on the cases discussed in this article, it would appear that trusts test the somewhat laggard abilities of investment treaties to entertain the complexity of modern day investment practices.