THE AUTHORS:
María Victoria (Mavi) Gómez, Associate at White & Case
Francisco Mateo Pavía, Counsel at the Court of Arbitration for Sport (“CAS”)
Pedro Aránguez, PhD Candidate at the University Carlos III (Madrid)
This article was featured in Jus Mundi‘s 2025 Arbitration Year in Review, an annual publication analyzing arbitration developments across 40+ jurisdictions on 6 continents. This edition brings together young practitioners and senior experts to capture the year’s most significant legislative reforms, enforcement trends, and institutional innovations.
Introduction
Arbitration in Spain has seen significant developments regarding the enforcement of investment arbitration awards against Spain, judicial decisions from Spanish courts dealing with longstanding arbitral doctrines, legislative initiatives on Alternative Dispute Resolution (“ADR”), and reforms of arbitral institutional rules.
Investment Arbitration Landscape: Enforcement on the Rise
Spain continues to dominate the global investment arbitration landscape in 2025, facing the consequences of its long-running disputes over renewable energy reforms. More than a decade after the government retroactively restructured its solar and renewable-energy subsidies regime, Spain remains embroiled in over 52 claims under the Energy Charter Treaty (1994) (“ECT”). Of the 52 arbitrations initiated to date, Spain has lost 27, several of which remain under challenge. This section outlines recent developments in the Spanish renewable-energy saga, focusing on the enforcement phase.
Spain is ranked among the world’s least compliant States in investment arbitration, with around 15 to 24 unpaid awards totaling approximately USD 1.5 billion. The State continues to resist enforcement abroad, invoking sovereign immunity and challenging jurisdiction in the United States (“US”), Australia, and the United Kingdom (“UK”). Its withdrawal from the ECT, effective on 17 April 2025, formally concluded a significant phase of its investment treaty exposure. However, the ECT’s 20-year sunset clause preserves investor protections for existing investments until 2045.
A Pivotal Year for Enforcement Claims
Enforcement within the European Union (“EU”) for intra-EU arbitrations remains blocked due to EU law and the European Commission’s ongoing state-aid interventions. In March 2025, the European Commission issued a landmark decision in Infrastructure Services (Antin) v. Spain, declaring the €101 million award constituted illegal state aid under EU law. The Commission prevented Spain from paying, reasoning that enforcement would breach Articles 107 and 108(3) of the Treaty on the Functioning of the European Union (“TFEU”). This precedent was aligned with the CJEU decisions in Achmea v. Slovakia (I) (“Achmea”) and Energoalians v. Moldova (“Komstroy”), reinforcing this idea of primacy of EU law on intra-EU investment arbitrations.
Beyond the EU, investors pursue enforcement in several jurisdictions:
- The United States of America: A major turning point came with the D.C. Circuit’s decision in NextEra v. Spain in August 2024, which confirmed that US courts have jurisdiction under the Foreign Sovereign Immunities Act (“FSIA”) to enforce ECT awards. The court rejected Spain’s argument that Achmea and Komstroy invalidated the arbitration agreement, treating those objections as issues of merits rather than jurisdiction. Later decisions, including Cube Infrastructure v. Spain, 14 August 2025, and Antin v. Spain, 30 September 2025, confirmed this reasoning.
- United Kingdom: In October 2025, in Operafund v. Spain, 10 November 2025,, the UK courts ruled that rights under an ICSID (International Centre for Settlement of Investment Disputes) arbitration award cannot be assigned to a third party. The case arose after the claimants, who had secured a €29.3 million award against Spain, assigned their rights to Blasket Renewable Investments LLC. Spain argued that ICSID awards were non-assignable. The court agreed, concluding that the ICSID framework contemplates enforcement only by the original parties to the arbitration, excluding third-party assignees. The judge further noted that the registration of the award in England did not create new rights capable of assignment. This decision is still subject to appeal.
- Australia: On 29 August 2025, 9REN Holdings, NextEra, and Blasket Renewable Investments (as assignee of RREEF and Watkins Holdings) sought to enforce four arbitral awards totalling €470 million against Spain. TheFederal Court of Australia upheld enforcement, finding that Spain waived sovereign immunity by ratifying the ICSID Convention and could not invoke EU law to resist payment.
First Signs of Compliance
Despite the State’s persistent resistance to enforcement, Spain showed its first instance of compliance in June 2025 with the JGC v. Spain award. Notably, Spain paid approximately €32 million to Blasket Renewable Investments, which had acquired the rights originally held by Japanese investor JGC Holdings Corporation (“JGC”). Because JGC was a non-EU investor, the European Commission’s state-aid concerns did not apply. Spain’s recent voluntary payment shows a meaningful shift.
Moving forward, enforcement proceedings are likely to continue across multiple jurisdictions, requiring investors to navigate a complex and evolving legal environment.
Judicial Decisions Shaping Arbitration
Spanish courts continue to review a growing number of arbitration cases, in line with Madrid’s consolidation as an arbitral hub. Two key cases provide interesting developments to longstanding arbitration doctrines.
EU Law, Public Policy and the Role of the CJEU in National Annulment Proceedings
Annulment proceedings in the case Cabify v. Auro continue to pose questions about the relationship between public policy and EU law, demonstrating diverging views between the Superior Court of Justice of Madrid (“TSJM”) and the Spanish Constitutional Court.
The award, issued by the Madrid Court of Arbitration, dealt with an exclusivity clause between two Spanish companies for transportation services and had considered the contract valid as not having breached competition rules. The claimant had brought set-aside proceedings before the TSJM, which partially annulled the award in its judgment of 22 October 2021, arguing that the tribunal had only considered Spanish law and had failed to apply the EU competition rule of Article 101 TFEU. The respondent resorted to the Spanish Constitutional Court, which reversed that decision in its judgment of 2 December 2024, reasoning that Article 101 TFEU was part of public policy but that the tribunal had correctly applied it, and that the TSJM had exceeded the due standard of limited review of the award. The Constitutional Court remanded the case to the TSJM, instructing it to issue a new judgment.
The TSJM, in its order of 20 March 2025, made a preliminary reference before the Court of Justice of the European Union (“CJEU”) before issuing a new judgment. The TSJM challenges the Constitutional Court’s view of a limited review of the award, even when this implies mandatory public policy of the EU, such as Article 101 TFEU. The preliminary reference will clarify the standard of review of awards when these imply mandatory rules of EU law and further deepens the diverging stances of the TSJM and the Constitutional Court regarding arbitration.
Criminal Liability of Arbitrators, Kompetenz-kompetenz and Arbitrator Immunity
The Spanish Supreme Court, in its judgment of 8 October 2025, upheld the criminal conviction of the arbitrator for contempt of court in the Heirs of the Sultanate of Sulu v. Malaysia saga. The TSJM had appointed the arbitrator in its judgment of 29 March 2019 based on a commercial arbitration agreement. The arbitrator subsequently issued a preliminary award on jurisdiction. Later, in the judgment of 29 June 2021, the TSJM annulled the appointment stating that Malaysia had not been properly served. The arbitrator considered there was a jurisdictional interference with his function, moved the seat of the arbitration from Spain to France, and issued a final award. Respondent issued a criminal complaint against the arbitrator, who was convicted for contempt of court.
The arbitrator argued, among other grounds, that his preliminary award on jurisdiction had not been set aside and that was the proper procedure to follow according to the Spanish Arbitration Act. The arbitrator contended that an arbitral tribunal has the power to decide its own jurisdiction and stated that the law clerk of the court who issued the order had no authority, therefore, he had an arbitral duty to continue the proceedings. The Spanish Supreme Court dismissed these arguments and upheld the conviction, arguing that for criminal law purposes, arbitrators cannot disagree with the interpretation of the courts by disobeying, and there was no criminal defence to contempt of court based on an arbitral duty.
Legislative and Institutional Rules Reforms
The Spanish Court of Arbitration (“Corte Española de Arbitraje” or “CEA”) and the Barcelona Arbitration Court(“Tribunal Arbitral de Barcelona” or “TAB”) have introduced comprehensive reforms to their arbitration rules, signalling Spain’s competitiveness as an arbitral seat. Additionally, new legislation on alternative dispute resolution mechanisms might foster arbitration as the preferred method to resolve commercial disputes.
Reforms to the CEA Arbitration Rules
The CEA’s new Arbitration Rules, which shall enter into force on 1 January 2026, introduce an “optional challenge procedure” —“impugnación opcional del laudo”— allowing parties to agree to an intra-institutional review mechanism that provides an additional layer of scrutiny before the award becomes final. This creates a second-tier arbitral review for manifest breach of substantive rules or manifest error in fact assessment, providing quality control whilst the award has no res judicata effect or enforcement power. Parties must expressly opt-in via their arbitration clause or an early agreement before the appointment of any arbitrator. A challenge tribunal appointed by the CEA reviews the challenged award, with limited evidence generally restricted to what was filed in the arbitration. The challenge proceedings result in a final award that remains susceptible to judicial annulment. This is particularly valuable for complex disputes where parties want additional arbitral scrutiny as a safeguard against potential annulment.
A second major development is the hyper-expedited procedure, which establishes a three-month timeframe from the statement of claim to the award for straightforward disputes. This requires express agreement before the response is filed. The procedure features compressed timelines (15 days for statements of claim and defence), no first procedural order, limited evidence, generally no hearings, and succinct awards.
The third key innovation concerns consolidation, with expanded criteria including:
- party agreement;
- same arbitration agreement;
- compatible agreements with common legal relationships or legal issues and risk of incompatible decisions. The CEA will issue a reasoned decision within 15 days and may, if necessary, constitute a new tribunal to safeguard the principle of party equality.
Beyond these principal developments, the CEA has introduced several refinements:
- extended disclosure obligations to representatives and third-party funders;
- an enhanced emergency arbitrator procedure with faster appointment (2 business days) and an option to issue awards;
- expanded post-award remedies, adding rectification for partial excess of jurisdiction;
- harmonisation of “internationality” criteria with United Nations Commission on International Trade Law (“UNCITRAL”) Model Law standards;
- enhanced institutional control over the seat of arbitration to avoid modifications; and
- shift from opt-in to opt-out for award publication.
Reforms to the TAB Arbitration Rules
The TAB‘s 2025 Arbitration Rules, which entered into force on 1 January 2025, introduced an emergency arbitrator procedure allowing parties to request urgent provisional measures before tribunal constitution. This critical addition aligned TAB with international best practices.
A second notable development addresses technology use and liability, with Article 51 clarifying that parties or arbitrators may use technology in proceedings and shall assume the risks and responsibilities derived from using their own or TAB’s technology. This article implicitly addresses the use of AI, a topic of paramount importance today.
The third key innovation is the preliminary review mechanism through Article 8, establishing a prima facie review of the arbitration agreement when the defendant does not respond, refuses arbitration, or raises exceptions regarding existence, validity or scope. This allows the TAB to conduct initial review before constituting the tribunal, potentially avoiding unnecessary costs if no valid agreement exists.
Other refinements include:
- mandatory disclosure of third-party funders;
- enhanced confidentiality protection through a two-year waiting period before publication and additional anonymisation requirements covering the subject of arbitration; and
- expanded post-award remedies adding rectification of partial excess of jurisdiction.
The Organic Law 1/2025
Finally, the enactment of Organic Law 1/2025 on measures for the efficiency of the Public Justice Service introduces mandatory alternative dispute resolution mechanisms as a prerequisite for accessing national courts in civil and commercial matters. As a private justice mechanism, arbitration remains exempt. With this additional obstacle to access to domestic courts, arbitration may increasingly be favoured as a rapid and final method to resolve commercial disputes, offering the parties a direct path to a binding resolution without the procedural hurdles now imposed in litigation.
Discover more insights into the latest developments in arbitration in 2025 from around the world now
ABOUT THE AUTHORS
María Victoria (Mavi) Gómez is an Associate at White & Case in the International Arbitration team, based in Madrid, and co-coordinator of MAD VYAP.
Francisco Mateo Pavía is Counsel at the Court of Arbitration for Sport (Lausanne, Switzerland) and co-coordinator of MAD VYAP.
Pedro Aránguez is a PhD Candidate at the University Carlos III (Madrid) and co-coordinator of MAD VYAP.
*The views and opinions expressed by authors are theirs and do not necessarily reflect those of their organizations, employers, or Daily Jus, Jus Mundi, or Jus Connect.
