Australia’s High Court Clarifies the Limits of Waiver of State Immunity Under the New York Convention

The High Court of Australia has delivered an important judgment in CCDM Holdings LLC v The Republic of India [2026] HCA 9 on the interaction between sovereign immunity and the New York Convention, confirming that a State’s ratification of the Convention does not, without more, constitute a waiver of jurisdictional immunity in enforcement proceedings. In doing so, the High Court of Australia distinguished between the New York Convention and the ICSID Convention, making clear that whether treaty ratification/accession amounts to a waiver of immunity will depend on the terms and structure of the particular treaty.

The decision continues the global trend of courts grappling with the boundaries between treaty-based enforcement regimes and domestic immunity doctrines and will be of particular interest to award creditors pursuing enforcement against States. It also adds an important comparative dimension to the developing case law in England, particularly following The Kingdom of Spain v Infrastructure Services Luxembourg S.À.R.L. and another; Republic of Zimbabwe v Border Timbers Ltd and another [2026] UKSC 9 on the ICSID Convention and the pending appeal in the English CC/Devas proceedings.

This update builds on our previous analyses of English court decisions addressing similar issues in the context of both the ICSID Convention and the New York Convention.

Background

The case arose out of efforts by investors to enforce an arbitral award of more than US$111 million against the Republic of India in Australia, following an investment treaty arbitration under the India-Mauritius BIT. The claimants sought recognition and enforcement in Australia under the New York Convention as implemented in Australian law.

At first instance, the Australian Federal Court held that India had waived its sovereign immunity by ratifying the New York Convention, reasoning that the Convention’s obligation to recognize and enforce awards gave rise to a necessary implication of waiver. The Full Federal Court overturned that result, holding that India’s “commercial reservation” to the New York Convention limited any waiver of immunity to disputes considered “commercial” under Indian law, and that the relevant BIT award did not fall within that category.

The investors then appealed to the High Court of Australia.

 The High Court of Australia’s Decision

The High Court of Australia ultimately dismissed the appeal with costs.

i) No waiver by ratification of the New York Convention alone

The High Court of Australia held that India’s ratification of the New York Convention did not itself amount to a waiver of foreign state immunity from the jurisdiction of Australian courts in proceedings to recognize and enforce the award.

ii) Waiver of immunity must be clear and unequivocal

The High Court of Australia reaffirmed that foreign states are immune from the jurisdiction of Australian courts unless a recognized exception applies, and that any waiver must be express or arise by implication that is clear and unmistakable. Mere ratification of the New York Convention was not enough to satisfy that standard.

iii) The High Court of Australia rejected the extension of the ICSID reasoning to the New York Convention

The High Court of Australia previously held in Kingdom of Spain v Infrastructure Services Luxembourg Sàrl [2023] 275 CLR 292 that the Kingdom of Spain had waived immunity from recognition and enforcement of arbitral awards by acceding to the ICSID Convention.

The High Court of Australia’s reasoning in CCDM Holdings now makes clear that the New York Convention does not have the same features as the ICSID Convention and, therefore, does not support the same inference of waiver by treaty ratification alone.

iv) Questions on reservations and scope remain open

Because it found that there was no waiver at all, the High Court of Australia declined to address arguments related to the New York Convention’s scope, including the effect of India’s commercial reservation, or India’s separate argument that the New York Convention may not apply to non-commercial or non-private-law disputes involving States.

Position in England

The position taken by the High Court of Australia is very similar, if not identical, to the position taken in England. In CC/Devas v Republic of India [2025] EWHC 964 (Comm), discussed in our earlier alert, the English High Court held that India’s ratification of the New York Convention did not amount to a waiver of adjudicative immunity. In the ICSID context, in March 2026, the UK Supreme Court held that accession to the ICSID Convention does amount to a clear submission to the adjudicative jurisdiction of the English courts for recognition and enforcement, while leaving immunity from execution intact. Read our previous alert on the UK Supreme Court’s decision.

Therefore, in both England and Australia, the analysis of whether a foreign state has waived immunity by ratifying or acceding to a treaty will depend on the terms and structure of the treaty in question.

The position in England as regards the New York Convention is not fully settled, however, because the English High Court’s decision in CC/Devas has been appealed, which was recently heard by the English Court of Appeal on March 24, 2026 (see CC/Devas (Mauritius) Ltd & Ors (Appellants/Claimants v The Republic of India (Respondent/Defendant)). The English Court of Appeal’s judgment will no doubt be highly anticipated.

Key Takeaways

1. Whether a foreign state has waived immunity by ratifying or acceding to the treaty will depend on the treaty in question

The clearest takeaway is that not all treaties have the same consequences for state immunity. As mentioned, accession to the ICSID Convention amounts to a clear submission to adjudicative jurisdiction for recognition and enforcement purposes. By contrast, ratifying the New York Convention, without more, does not carry the same consequence.

2. Waiver of immunity still requires a clear and unequivocal basis

The courts will not infer waiver lightly. Given the principle of international comity, a foreign state remains immune from the jurisdiction of domestic courts unless a recognized exception applies, and general treaty obligations to recognize and enforce awards will not suffice unless the treaty clearly supports that result.

3. Enforcing non-ICSID awards against States may be more difficult

The decision underscores the risk that parties seeking to enforce non-ICSID awards against States in England and in Australia will face significant hurdles in relation to enforcement, including the risk that the awards will be unenforceable in the jurisdiction concerned.

4. Important questions on reservations remain open

Although the High Court of Australia did not decide the effect of India’s commercial reservation, that issue remains significant. A substantial number of New York Convention contracting states have adopted a commercial reservation under Article I(3), which may affect enforcement of non-commercial awards, including some investment treaty awards, in those jurisdictions, even where a state has submitted to the jurisdiction of their respective courts.

Conclusion

The High Court of Australia’s decision is a significant development in the evolving jurisprudence on sovereign immunity and arbitral award enforcement. Its central message is not that treaty-based waiver is impossible, but that it must be grounded in the particular treaty said to give rise to it. On that analysis, the New York Convention does not, by ratification alone, constitute a waiver of jurisdictional immunity.

Read alongside the High Court of Australia’s previous decision in Kingdom of Spain, and the UK Supreme Court’s recent ICSID judgment of similar name, there is now a distinction between ICSID enforcement, where treaty accession amounts to a submission to adjudicative jurisdiction, and the enforcement of awards under the New York Convention, where domestic courts may be unwilling to infer the same result absent clearer language in the Convention itself. With the CC/Devas case now on appeal, it remains to be seen whether the English Court of Appeal will preserve that distinction.

We are grateful to our London Trainee Solicitor, Diya Gupta, for her contributions to this client alert.