In Mobil Corporation and others v Bolivarian Republic of Venezuela (ICSID Case No ARB/07/27), an ICSID tribunal had to consider whether it had jurisdiction over Mobil's claims for compensation following Venezuela's nationalisation of certain oil-related projects. The key issue was whether Venezuela had consented to ICSID arbitration through the relevant Venezuelan "investment law", through the applicable bilateral investment treaty (BIT) between the Netherlands and Venezuela, or through both. In its assessment of what standard of interpretation should be applied when interpreting the consent contained in the investment law, the tribunal analysed a number of cases in which ICSID tribunals have considered which rules of interpretation to apply. It concluded that legislation and, more generally, unilateral acts by which a state consents to ICSID jurisdiction must be considered as "standing offers" to foreign investors under the ICSID Convention: "those unilateral acts must accordingly be interpreted according to the ICSID Convention itself and to the rules of international law governing unilateral declarations of states".

The alleged consent contained in the investment law was ambiguous and obscure and the tribunal therefore had to consider whether they should apply the principle of effectiveness when interpreting the relevant provision. This rule requires a treaty to be interpreted in such a way as not to render portions of the text redundant or inutile. Although the tribunal in Southern Pacific Properties (Middle East) Ltd v Arab Republic of Egypt (ICSID Case No ARB/84/3 (Decision on Jurisdiction)) did resort to the principle of effet utile in the interpretation of a unilateral declaration by a state, the tribunal in the present case preferred the later ruling in Fisheries Jurisdiction (Spain v Canada) (Jurisdiction of the court) ICJ Reports 1998, p 432, which required a unilateral declaration by a state to be interpreted in a manner compatible with the effect sought by the state making it.

Having reviewed the legislative history of the investment law, the tribunal concluded that Venezuela had not intended to consent in general to ICSID arbitration by enacting the legislation. However, the tribunal found that it had jurisdiction on the basis of the BIT in relation to some of the claims.

The case is of interest as it follows the approach in previous decisions to the interpretation of unilateral acts by states by reference to the international law standard. It also clarifies that although the principle of effet utile applies to the interpretation of the law of treaties, it does not apply to unilateral declarations by states, such as the investment legislation invoked in this case.