“The Emerging Jurisprudence on the Most-Favoured-Nation Treatment in Investment Arbitration,” in Investment Treaty Law: Current Issues III, at 241 (A. Bjorklund, I. Laird, S. Ripinsky eds., BIICL, 2009)

The fast-growing development of investment arbitration on the basis of investment protection treaties has contributed to the development of an important body of case law on issues that, although familiar in the context of public international law, appear as novel in the context of investment arbitration. Issues such as ‘national treatment’, the effect of ‘most-favoured-nation’ treatment, the effect of the so-called ‘umbrella’ clauses or the ‘state of necessity’ as a cause of exoneration of the State’s international responsibility are topics that remain today hotly debated and have yet to yield a consistent body of law.

The specific example of the most-favoured-nation clause is of particular interest as, unlike in the case of the ‘umbrella’ clause, it is not the concept as such that raises difficulty. The most-favoured nation clause is perceived in almost straightforward terms in situations where it is sought to be applied to the provisions setting forth the investor’s classic substantive protection under an investment treaty. Diverging views surface, however, in situations where it is sought to be applied to the dispute resolution mechanism of a treaty. Each of these situations is examined in turn in this article, with particular focus on the study and analysis of the arbitral case law.