EU Illegal Hydrocarbon Tax: Supreme Court Centralizes Claims Against the State in 2026

Key data

If your company paid the autonomous section of the Hydrocarbon Tax in Spain, you have the right to claim from the State what you overpaid. The Court of Justice of the European Union (CJEU) declared that section contrary to Community Law on May 30, 2024 in the judgment of the DISA case (C-743/22), and now the Supreme Court has taken a decisive step to organize the avalanche of claims expected.

The Agreement of the Governing Board of the Supreme Court of June 17, 2026, published in the BOE on August 6, 2026, concentrates all administrative litigation appeals on state legislative liability in the Provisional Section of Sole Competence (former Eighth Section) of the Third Chamber. Files already registered in the Fifth Section will be transferred to this new specialized section.

What does this regulation establish?

The Supreme Court has made a judicial organization decision with very relevant practical consequences for any company wishing to claim. In essence, it establishes three things:

• Centralization of all appeals: all lawsuits on state legislative liability arising from the autonomous section of the Hydrocarbon Tax go to a single section.
• Transfer of existing files: cases already registered in the Fifth Section move to the Provisional Section of Sole Competence to ensure consistency.
• Uniform criteria: by concentrating all cases in the same specialized section, the Supreme Court seeks to avoid contradictory rulings and provide legal certainty to claimants.

The origin of all this is the CJEU judgment of May 30, 2024 in case C-743/22 (DISA), which declared that the autonomous section of the Hydrocarbon Tax was incompatible with EU Law. This opens the avenue of state legislative liability: the mechanism by which a taxpayer can require the State to reimburse what was paid under a rule that later turns out to be illegal.

Economic and operational impact

Centralization at the Supreme Court has direct implications for the cost and strategy of any claim:

• Greater legal predictability: with a single section resolving all cases, the jurisprudence generated will be uniform. This reduces uncertainty about the outcome and facilitates the decision to claim.
• Potential impact on thousands of taxpayers: the agreement itself recognizes that these lawsuits "may affect thousands of taxpayers" who bore the tax. The expected volume of claims justifies the creation of a specialized section.
• Active judicial avenue: energy and transport sector companies formally have an open avenue to claim reimbursement of what was unduly collected for this purpose.
• Risk of statute of limitations: the action for state liability has time limits. Failing to act in time may result in losing the right to claim potentially significant amounts.

Who does it affect?

• Energy sector companies that operated as taxpayers or passed on the autonomous section of the Hydrocarbon Tax.
• Transport sector companies (vehicle fleets, freight transport, logistics) that economically bore the tax.
• Large industrial fuel consumers that paid the autonomous section.
• Any taxpayer —individual or legal entity— that has paid amounts for the autonomous section of the Hydrocarbon Tax and has not recovered them.
• Tax advisors and law firms that manage tax claims for clients in the above sectors.

Practical example

A road freight transport company that during several fiscal years paid the autonomous section of the Hydrocarbon Tax on its diesel consumption can file an administrative litigation appeal for state legislative liability before the Supreme Court, citing the CJEU judgment of May 30, 2024 (DISA case, C-743/22).

Thanks to the agreement published on August 6, 2026, that appeal will be assigned directly to the Provisional Section of Sole Competence (former Eighth Section) of the Third Chamber of the Supreme Court, along with the rest of similar claims. This means that the criterion that resolves its case will be the same applied to all other companies in an analogous situation, which gives greater predictability to the outcome and reduces the risk of disparate rulings.

If that same company had already filed its appeal and it was registered in the Fifth Section, the file will be transferred ex officio to the new specialized section, without any additional action required by the claimant.

What should companies do now?

1. Review if you paid the autonomous section of the Hydrocarbon Tax: consult with your tax advisor the returns for the periods in which this section was in force and quantify the total amount borne.
2. Evaluate statute of limitations: the action for state liability has legal time limits. Act urgently to not lose the right to claim. Consult a lawyer specialized in tax law or administrative litigation.
3. Prepare documentation: gather self-assessments, invoices and payment receipts for the tax that prove the amount actually borne.
4. File the appeal before the Supreme Court: the avenue is the administrative litigation appeal for state legislative liability. As of August 6, 2026, all these matters are processed in the Provisional Section of Sole Competence (former Eighth Section) of the Third Chamber.
5. If you already have an appeal in progress: verify with your legal representative if the file was in the Fifth Section, as it will be transferred ex officio to the new specialized section. No additional action is necessary, but it is advisable to confirm it.

Official source

Consult complete regulation in official source (BOE-A-2026-17121)

Notice: This article is for informational purposes only and does not constitute legal advice. For specific decisions, consult a qualified professional. Source: https://www.boe.es/diario_boe/txt.php?id=BOE-A-2026-17121