ICSID Waives, New York Does Not: The 2026 Sovereign Immunity Trilogy and What it Means for Enforcement

Early into 2026, three superior courts decided whether a state's adherence to a multilateral convention waives its sovereign immunity at the enforcement stage. On 24 February 2026, the Singapore High Court in NextEra Energy Global Holdings BV v Kingdom of Spain (“NextEra”) held that Spain's accession to the ICSID Convention amounts to submission to Singapore's jurisdiction for recognition and enforcement. On 4 March 2026, the UK Supreme Court reached the same conclusion in the joined appeal of Kingdom of Spain v Infrastructure Services Luxembourg S.À.R.L. and Republic of Zimbabwe v Border Timbers Ltd (together, “Infrastructure/Border Timbers”). On 8 April 2026, the High Court of Australia in CCDM Holdings LLC v Republic of India (“CCDM”) held that India's ratification of the New York Convention did not amount to submission to Australia’s jurisdiction.

The doctrinal instability from which this trilogy emerges had already been visible in 2024 (as reviewed on this Blog), which produced conflicting approaches to the immunity question. This trilogy now resolves that, consolidating the common law approach to sovereign immunity in terms of a treaty-specific doctrine. This post traces that doctrine and draws out what it means for drafters and treaty architects.

The ICSID Consensus

The UK Supreme Court in Infrastructure/Border Timbers and the Singapore High Court in NextEra reached the same conclusion nine days apart. In the UK appeals, the judges held unanimously that Article 54(1) of the ICSID Convention is a “clear and unequivocal expression” of consent to the adjudicative jurisdiction of the courts of other contracting states, sufficient to engage Section 2(2) of the State Immunity Act 1978. Neither Spain nor Zimbabwe could therefore resist registration of the awards against them under the Arbitration (International Investment Disputes) Act 1966. In NextEra, Justice Andre Maniam reached the same conclusion under Sections 4 and 11 of the State Immunity Act 1979, read with the Arbitration (International Investment Disputes) Act 1968. He also rejected Spain's intra-EU objection. Spain argued, relying on Slowakische Republik (Slovak Republic) v. Achmea BV (“Achmea”) and Republic of Moldova v. Komstroy LLC (“Komstroy”), that intra-EU Energy Charter Treaty (“ECT”) arbitration clauses are incompatible with EU law. Justice Maniam held, to the contrary, that Article 26 of the ECT gives rise to a valid arbitration agreement, and EU law is not a recognised basis for resisting an ICSID award in a Singaporean court.

The reasoning by the Singapore High Court and the UK Supreme Court converge on three features of ICSID. Articles 53 to 55 of the ICSID Convention establish a self-contained scheme. Each contracting state undertakes to recognise an award “as binding” and to enforce its pecuniary obligations “as if it were a final judgment of a court in that State”. Article 55 expressly preserves only immunity from execution, which leaves adjudicative immunity displaced by negative implication. A state cannot simultaneously promise that other contracting states “shall” enforce awards against it, while invoking immunity from the proceedings that give effect to that promise. The practical gap between adjudicative immunity and execution immunity, and the growing sophistication of states in shielding sovereign wealth from attachment, is covered on this Blog.

That gap notwithstanding, courts in the US, Malaysia, New Zealand, and Australia had already taken the same view on the adjudicative question, as the UK Supreme Court observed in Infrastructure/Border Timbers, and NextEra confirmed it at the highest level in a further jurisdiction. The reasoning is treaty-specific, and it cannot be generalised. CCDM demonstrates why.

The New York Convention Carve-Out

In CCDM, the High Court of Australia held that India's ratification of the New York Convention did not, without more, constitute waiver of jurisdictional immunity, thereby reversing the Federal Court’s ruling. Because the High Court found no waiver, it did not need to reach the question of India’s commercial reservation under the Convention. The same court had, three years earlier, found the ICSID waiver in Kingdom of Spain v Infrastructure Services Luxembourg S.À.R.L. not jurisdiction-specific, confirming that the distinction is treaty-specific.

Two features of the New York Convention drove that conclusion. Unlike the ICSID Convention, it is silent on sovereign immunity. There is no analogue of Article 55, which preserves one category of immunity and displaces another. As noted in CCDM, the travaux préparatoires of the New York Convention contain limited and conflicting consideration of state immunity. Article III, the principal textual hook for the waiver argument, contemplates enforcement “in accordance with the rules of procedure of the territory where the award is relied upon”. Those rules, in every Convention state, include rules of foreign state immunity. Article III therefore preserves domestic immunity doctrines rather than displacing them. There is no equivalent of ICSID's “as if it were a final judgment” obligation to support waiver by necessary implication.

CCDM is more than an Australian outlier. The English High Court had reached essentially the same conclusion a year earlier in CC/Devas (Mauritius) Ltd v Republic of India (“CC/Devas”). Sir William Blair held that India's ratification of the New York Convention did not amount to submission under Section 2(2) of the State Immunity Act 1978. The reasoning, analysed in an earlier post on this Blog, tracked the argument the High Court of Australia would later adopt almost in terms. The Court of Appeal heard the appeal for CC/Devas on 24 March 2026 and has reserved judgment. Its decision will determine whether the convergence between English and Australian law on this point survives at the appellate level. The fragmentation of that case law across Australia, Canada, and the United Kingdom before CCDM is mapped in detail on this Blog, which describes the New York Convention jurisprudence on immunity as scattered and incoherent.

The practical consequence is clear. For ICSID awards, Infrastructure/Border Timbers and NextEra put enforcement beyond serious doubt in the UK and Singapore. For New York Convention awards against a state, ratification is not sufficient in Australia or (on current authority) England, at least among common law jurisdictions applying a clear-and-unmistakable standard to treaty-based waiver. The creditor's alternatives are narrower: an express waiver, a post-dispute submission, or a finding under the arbitration exception in Section 9 of the State Immunity Act 1978, which removes immunity where the state has agreed in writing to submit a dispute to arbitration. However, Infrastructure/Border Timbers left open whether the arbitration clause of a bilateral investment treaty qualifies as such an agreement where Section 2(2) ICSID waiver is unavailable.

Implications for Drafters and Treaty Architects

The trilogy makes an express waiver of sovereign immunity, covering adjudicative jurisdiction and (so far as permissible) execution, effectively a standard drafting requirement in any clause where enforcement against a sovereign may arise. The reason is not that any one forum is restrictive. It is that pro-arbitration common law jurisdictions are applying a clear-and-unmistakable standard to New York Convention waiver and finding it unmet by ratification alone. An express waiver is significantly cheaper at the contract stage than post-award.

For commercial contracts with sovereign counterparties, the clause should state, at minimum, that the state party irrevocably waives immunity from the jurisdiction of the courts of the specified forum in connection with any proceedings to recognise, register, or enforce any award arising out of the arbitration clause, and that the waiver is not affected by any subsequent change in the law of the state party. The clause should separately address execution immunity and identify the assets to which the waiver extends, since neither Infrastructure/Border Timbers nor NextEra resolved that question.

For treaty architects, the clearest structural response is to replicate the mechanism in Articles 54/55 of the ICSID Convention in future investment treaties providing for non-ICSID arbitration. The technique is to build in an express obligation, analogous to Article 54(1), requiring each party to recognise and enforce awards rendered under the treaty as if they were final judgments of its own courts. Combined with a clause expressly preserving only execution immunity, this displaces adjudicative immunity by necessary implication and meets the clear-and-unmistakable standard Infrastructure/Border Timbers confirmed. Future treaties providing UNCITRAL, SCC, or ICC arbitration as the sole mechanism should address this gap expressly; the absence of an Article 54-type obligation in the ECT is precisely why non-ICSID ECT creditors face greater enforcement uncertainty than ICSID ECT creditors under the same instrument.

Conclusion

The 2026 trilogy is best read not as fragmentation, but as the consolidation of a treaty-specific doctrine. ICSID accession waives adjudicative immunity. New York Convention ratification, standing alone, does not. That position is now broadly shared across the UK, Singapore, the US, and Australia.

The instability lies elsewhere. The UK Supreme Court left open the arbitration exception under Section 9 of the State Immunity Act 1978, a question that remains live wherever Section 2(2) is unavailable; the intra-EU objection under Achmea and Komstroy remains contested before EU Member State courts and institutions, independent of the immunity analysis. For creditors and drafters, the practical conclusion is clear regardless of which convention governs the underlying arbitration. In any contract that may be enforced against a sovereign, an express waiver of immunity is the precondition for accessing the enforcement system the conventions were designed to create. For treaty architects, the trilogy's deeper lesson is structural, that enforcement certainty is a product of treaty design, not treaty ratification. The CC/Devas appeal, with judgment reserved, will determine whether English law closes the New York Convention gap or confirms it. Either way, the answer for drafters is the same: treaty ratification alone is not enough.