Investment Arbitration Between Public and Private Foundations: Qualification of Bilateral Investment Treaties and the Prevention of Fragmentation of International Law

The article presents the results of a study into the legal nature of investment arbitration through the lens of the interaction between public-law and private-law elements affecting the characterisation of bilateral investment treaties and the interpretative approaches to dispute settlement clauses. Particular attention is paid to the risks of fragmentation of international law arising from the concurrent operation of specialised treaty regimes, the competition of jurisdictional mechanisms, and divergent approaches to applicable law. The study substantiates the relevance of systemic and teleological treaty interpretation aimed at safeguarding the coherence of international legal regulation and the predictability of adjudicatory practice, while avoiding the transposition of commercial-contract logic onto international agreements. It also emphasises the need to draw clearer boundaries between “jurisdiction” and “applicable law” and to account for the role of domestic law in investor protection mechanisms, while maintaining the primacy of the international-law nature of the obligations concerned.