Briefing

ICSID award assignments: why the English Court of Appeal rejected Blasket’s bid to enforce

The critical question in Operafund was not simply whether the Convention on the Settlement of Investment Disputes between States and Nationals of Other States 1965 (the ICSID Convention) prohibited assignment. It was whether international law gave an investor the power to transfer its award rights without the debtor State’s consent. The Court of Appeal’s answer exposes the limits of treating an ICSID award as an ordinary tradeable debt: a private agreement cannot, by itself, change the person entitled to enforce the State’s international-law obligation.

In our earlier article¹, we considered the Commercial Court’s decision in Operafund Eco-Invest SICAV plc and another v Spain [2025] EWHC 2874 (Comm), which rejected Blasket Renewable Investments LLC’s (Blasket) attempt to replace the original investors in English proceedings following an assignment of their ICSID award. On 2 November 2026, the Court of Appeal dismissed the appeal in Operafund Eco-Invest SICAV plc and others v The Kingdom of Spain [2026] EWCA Civ 1392.

The outcome upheld the restriction on Blasket enforcing in its own name, but not every aspect of the Commercial Court’s reasoning. In particular, the decision is not a blanket prohibition on assigning every award arising under the Energy Charter Treaty 1994 (ECT). The distinction between ICSID awards and awards governed by domestic law is central to understanding its reach.

Background and the appeal

Operafund Eco-Invest SICAV plc and Schwab Holding AG (the Investors) obtained an ICSID award of €29.3 million against Spain following changes to Spain’s renewable-energy tariff regime. The award was registered in England and Wales in September 2021 under the Arbitration (International Investment Disputes) Act 1966 (the 1966 Act). In January 2024, the Investors entered into a Swiss-law agreement purporting to transfer their rights in relation to the award to Blasket.

Blasket sought substitution under CPR 19.2(4), which required it to establish that the relevant interest had passed to it. The appeal concerned two principal questions:

whether the rights under the ICSID award could be assigned; and
whether registration had created a separate English-law right capable of assignment even if the underlying award rights were not assignable.

Our earlier article also addressed the Investors’ reliance on the favourable Australian decision as creating an issue estoppel against Spain. The Court of Appeal’s decision instead addressed the substantive assignment and registration questions.

Assignment requires a legal power, not merely the absence of a prohibition

Foxton LJ’s reasoning began with the distinction between rights arising under domestic (or municipal) law and rights arising under international law. An ICSID award derives its binding force from the ICSID Convention and operates within its self-contained regime. In seeking recognition and enforcement, the creditor asserts treaty rights, not merely a debt governed by domestic law (paragraph 96).

Blasket relied on the absence of an express prohibition on assignment in the ICSID Convention or the ECT. The court considered that this approached the question from the wrong direction. Even assuming that international law did not prohibit the transaction, that would not establish its legal effect against Spain. Blasket needed to identify a power to change the person to whom the State owed its obligation, not merely a freedom to enter into the assignment agreement (paragraphs 80–91).

The court accepted that customary international law prevents treaty rights from being assigned without the obligor State’s consent, and found no established exception for rights conferred on investors. That is more than a finding that the treaties contain no express permission: the court identified a default rule of non-assignability which Blasket had not displaced. The developing secondary market and decisions permitting assignment did not establish the sufficiently consistent State practice and acceptance as law needed to support its case (paragraphs 59–61, 75–81). The court also recorded that no argument had been advanced that a power of assignment arose from ‘general principles of law’ under Article 38(1)(c) of the ICJ Statute (paragraph 38).

That conclusion was sufficient to dispose of the assignment ground. Foxton LJ nevertheless addressed the ECT and Article 54(2) because those issues had been fully argued and underpinned the Commercial Court’s decision (paragraph 99). The commercial distinction is fundamental: an assignment effective between seller and purchaser under its governing law does not, by itself, transfer the right to enforce the State’s international-law obligation.

Article 54(2): who may seek recognition and enforcement?

Although its conclusion on Ground 1A made it unnecessary to decide the remaining treaty-construction grounds, the court went on to identify a further obstacle in Article 54(2): who may invoke the Convention’s recognition and enforcement machinery? Blasket argued that “a party” in Article 54(2), unlike “a party to the dispute”, could include an assignee. Foxton LJ rejected that reliance on the omitted words. Read as a whole, Article 54 gives effect to Article 53, which makes the award binding on the parties and requires them to comply with it. Article 54(2) identifies who can invoke those obligations; it does not introduce a new class of persons entitled to enforce (paragraphs 129–133).

The court did not, however, endorse the Commercial Court’s reliance on the requirement to produce a certified copy of the award. An assignee could also produce that document, and a comparable requirement under the New York Convention does not prevent enforcement by assignees. The persuasive point was the relationship between Articles 53 and 54, not the documentary formality (paragraph 133).

Nor could the timing of the assignment overcome that obstacle. The Investors had begun the English proceedings before assigning their rights, but Article 54(2) is not merely an entry requirement satisfied permanently when an application is issued. A party seeks recognition and enforcement throughout the process until the relevant relief is obtained, refused or abandoned. Starting proceedings in the original creditors’ names therefore did not permit Blasket to take over as the substantive applicant (paragraphs 138–139).

Same result, but not the same reasoning: the ECT qualification

The court’s treatment of Article 15 of the ECT differed from that of the Commercial Court. Article 15 expressly protects certain assignments and subrogation arrangements where a State or designated agency indemnifies an investor. Spain argued that this specific provision implied the exclusion of other assignments.

The Court of Appeal rejected that inference. On the assumption that international law otherwise supplied a power of assignment, Article 15 would not exclude it. The provision has distinct work to do: it covers claims as well as awards and expressly permits indemnifying States to exercise investor rights through mechanisms otherwise reserved to investors. It was therefore unnecessary to read it as implicitly prohibiting other assignments (paragraphs 108–112). Blasket succeeded on this point, but it did not overcome the prior conclusion that the necessary international-law power had not been established.

The distinction between an ICSID award made under the ECT and other outcomes available under that treaty is therefore essential. Foxton LJ indicated, without deciding the point, that enforcement of an award governed by municipal law could involve the assertion of a domestic-law right rather than a treaty right. The judgment does not establish that all ECT awards are unassignable (paragraphs 95–97).

Registration does not create a separately assignable enforcement right

Registration could not supply the entitlement which the assignment had failed to transfer. Blasket argued that registration under the 1966 Act created a new English-law enforcement right assignable independently of the award. Section 2 gives the registered award’s pecuniary obligations the same force and effect for execution as a High Court judgment. Applying the reasoning in Micula v Romania [2018] EWCA Civ 1801 and [2020] UKSC 5, the court treated that equivalence as limited: it supplies execution machinery, not a new substantive entitlement capable of separate assignment (paragraphs 143 and 152–155).

Two connected reasons explain the rejection. First, assignability determines who is entitled to payment, a substantive question preceding enforcement or execution and governed here by international law. Second, there is one award and one payment obligation, even where enforcement is pursued in several countries. Allowing national enforcement rights to be assigned separately would put those rights in different hands without transferring the underlying entitlement. English law does not permit the remedy to be detached and assigned independently of the right it enforces (paragraphs 147–148 and 157–159). Registration was therefore no route around the failure of the underlying transfer.

Why the foreign decisions did not change the answer

The disagreement with foreign courts was not simply a choice between competing outcomes. Several decisions permitting assignment asked whether the treaties prohibited it, without resolving the prior question of the source of the international-law power to assign. Others concerned awards operating under municipal law, rather than ICSID awards deriving their force from international law. Those differences limited both their persuasive force and their value as evidence of an established customary rule (paragraphs 63–78). The court also reached its own contextual interpretation of Article 54(2), notwithstanding contrary decisions in the United States, Australia and the Netherlands (paragraph 137(i)). Males LJ also emphasised that these first-instance and interim decisions did not necessarily represent the final and settled position in their respective jurisdictions (paragraph 164).

The Australian proceedings concerning the same award remain particularly important: according to the information before the Court of Appeal, the appeal had been heard and judgment was expected in January 2027 (paragraph 67). For purchasers, the present divergence makes enforcement jurisdiction a central transaction risk. Acceptance of an assignment in one forum cannot safely be assumed to confer equivalent standing in England.

Comment: important limits and practical consequences

What was decided. A voluntary assignment without Spain’s consent did not entitle Blasket to replace the Investors as the person seeking recognition and enforcement of the ICSID award. Registration in England did not create an independently assignable enforcement right. The decision concerns original award creditors who remain in existence; it should not be extended uncritically to every transfer of an award or every award made under the ECT.

What remains open. Transfers on death or insolvency, corporate succession and the effect of a State’s consent on an assignee’s ability to invoke Article 54(2) were left for a case in which they arise (paragraph 137(ii)–(iii); Males LJ at paragraphs 165–166). Economic participation must also be distinguished from standing to enforce. At paragraph 116, Foxton LJ referred to alternative monetisation mechanisms and quoted the judge’s observation that, subject to the pending set-aside application, the Investors remained entitled to enforce, with clause 7 of the assignment agreement providing for Blasket to control the process and receive recoveries. This was not a general approval of all trust, control or proceeds-sharing structures.

Practical implications. Purchasers should distinguish acquiring an economic interest in an award from acquiring the entitlement to enforce it. Transaction documents should address the original creditors’ continuing role and cooperation, control and funding of proceedings, allocation of recoveries, and the consequences if substitution is refused. The central lesson is that neither the assignment agreement’s governing law nor English registration can, by itself, bridge a failure to transfer the underlying international-law entitlement.

Whether the decision will be the subject of a further appeal remains to be seen. We will report on any significant developments.

The judgment can be found here.

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