Operafund Eco-Invest v Kingdom of Spain: Court of Appeal bars assignment of ICSID award

The Court of Appeal has held that an investor cannot assign an ICSID award against a state to a third party without that state's consent, so that the assignee can enforce it in England. In Operafund Eco-Invest SICAV plc v Kingdom of Spain [2026] EWCA Civ 1392, Lord Justice Foxton, with whom Lord Justice Males and Lord Justice Lewison agreed, dismissed an appeal by Blasket Renewable Investments LLC against the refusal of HHJ Pelling KC to substitute it as a party.

An award sold to an enforcement vehicle

Two investors obtained a €29.3 million award against Spain under the Energy Charter Treaty in 2019, one of 51 known arbitrations arising from changes to Spain's renewables tariffs. The award was registered in England under the Arbitration (International Investment Disputes) Act 1966 in 2021. Spain's application to set the registration aside, including a state immunity challenge, remained pending.

In January 2024 the investors assigned the award to Blasket, a Delaware company incorporated to acquire investment treaty awards. Blasket sought substitution under CPR 19.2(4), which required it to show a valid assignment.

No power to assign

Foxton LJ treated the source of any power to assign as the anterior question. It was common ground that neither the Energy Charter Treaty nor the ICSID Convention confers one, and that assignability is governed by international law. Relying on Lord McNair's The Law of Treaties and International Law Commission commentary, he accepted that treaty rights between states are not assignable without the obligor's consent. He saw real force in applying the same position to rights that treaties confer on investors.

The decisions Blasket relied on, from New York, Australia and Rotterdam, did not establish a customary rule. Most asked whether the Convention prohibited assignment rather than whether a power existed, and several concerned awards on the municipal plane. They were also recent, and came from courts of states not "specially affected". Blasket was effectively asking the court to develop international law beyond what other states accept.

The court also rejected the argument, drawn from the Lotus principle, that silence in international law permits assignment. Even if the principle extends to non-state actors, it would give a liberty, not a power to alter the obligations a state owes.

Article 54(2) and the 1966 Act

Although unnecessary to the result, the court considered the remaining grounds. Foxton LJ would not have read Article 15 of the Treaty, which deals with state subrogation, as excluding assignment had a general power existed. He agreed with the judge, however, that "a party seeking recognition or enforcement" in Article 54(2) of the ICSID Convention means a party to the award. That reading departed from first-instance decisions in the United States, Australia and the Netherlands, a divergence he called unfortunate but unavoidable.

On Ground 2, section 2 of the 1966 Act supplies machinery for execution and creates no new substantive right capable of assignment independently of the award. Allowing such a right would divide the indivisible, and could leave enforcement rights in different hands in different jurisdictions.

Reserved points

Males LJ accepted it may be desirable for such awards to be assignable, but said that is not the current state of international law. He hoped the reasoning would contribute to eventual international consensus. He reserved two questions: whether involuntary transfers, such as on insolvency, death or corporate succession, would permit enforcement by the transferee, and whether an assignee could enforce where a state consented to the assignment. Lewison LJ agreed, describing Spain's failure to comply with the award as regrettable.