International law as the basis for extending arbitration agreements concluded by States or State Entities to non-signatories

This article explores the role of international law in relation to the extension of arbitration agreements contained in contracts concluded by States (or State entities) with non-signatory State entities (or States). As contract-based arbitrations involving States or State entities are on the rise, identifying the legal framework governing which parties are covered by the relevant arbitration agreements is of practical importance. The analysis demonstrates that international law forms part of the relevant law, alongside other applicable laws including law of contract, law of the seat and transnational law, concerning the extension of arbitration agreements concluded by States or State entities to non-signatories. Previous analyses have neglected the role of international law by not distinguishing contract-based arbitrations involving private parties from contract-based arbitrations involving States or State entities. Public international law recognises that arbitration agreements can be extended to non-signatories on the basis of implied consent, or abuse of separate legal personality and estoppel. Therefore, foreign investors can rely on international law to extend arbitration agreements to non-signatories in arbitrations conducted under investment contracts concluded by States or State entities, even if the relevant domestic law is agnostic or hostile to this. This has significant legal, and practical, importance