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italaw180974 - 9REN v. Spain, Supplemental Brief for Petitioner Kingdom of Spain, June 8, 2026.pdf

8 Jun 2026
9REN Holding S.a.r.l v. Kingdom of Spain, ICSID Case No. ARB/15/15
Supplemental Brief for Petitioner Kingdom of Spain
Document Details:
LISTED PARTICIPANTS
Supplemental Brief for Petitioner Kingdom of Spain
Participants listed are for this document only and may not include all participants involved in the entire case. Always consult the original documents.
Claimant appointee
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Arbitrator(s)
Sole Arbitrator
ICSID Annulment Committee president
ICSID Annulment Committee members
WTO Appellate Body members
WTO Appellate Body chair
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Respondent's law firm
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Claimant's expert firm
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Document Summary
Supplemental Brief for Petitioner Kingdom of Spain
This summary note is machine-generated. Always consult the original materials.

Procedural Posture

This document is a supplemental brief filed by the Petitioner, the Kingdom of Spain, before the Supreme Court of the United States. It is submitted in support of Spain's petition for a writ of certiorari to review a judgment of the U.S. Court of Appeals for the District of Columbia Circuit concerning the enforcement of an arbitral award rendered against it.

Key Legal Issues

The brief argues for Supreme Court review on two principal questions. The first concerns the standard of review under the Foreign Sovereign Immunities Act (FSIA) for determining the existence of a valid arbitration agreement. Spain contends that whether a foreign sovereign consented to arbitration is a jurisdictional question requiring de novo judicial review, contrary to the D.C. Circuit's holding which treated it as a merits question subject to a highly deferential standard. The second issue is whether the doctrine of forum non conveniens is available as a defense in actions brought in U.S. courts to enforce foreign arbitral awards against sovereign states.

Petitioner's Arguments

Spain asserts that the D.C. Circuit's decision is erroneous and creates a circuit split with the Second and Fifth Circuits on the FSIA question. It argues that the ruling permits the withdrawal of sovereign immunity without a federal court ever independently determining whether the sovereign consented to arbitrate. Spain contends that under a proper de novo review, European Union law would demonstrate that no valid arbitration agreement was ever formed for intra-EU disputes under the Energy Charter Treaty (ECT), thereby precluding the arbitration exception to sovereign immunity.

The brief also refutes the U.S. government's recommendation (in its amicus brief) to deny certiorari based on "vehicle" objections. Spain argues that speculation about the ultimate outcome on remand is immaterial to the certworthiness of a critical and recurring question of law with significant foreign-relations implications. Regarding the second question, Spain maintains that the D.C. Circuit's categorical rejection of forum non conveniens is incorrect and deepens another circuit split. The brief concludes by urging the Court to grant the petition for certiorari.