Key data
| Regulation | Resolution of July 24, 2026, by CNMC — Service of process in administrative litigation 4/190/2026 |
|---|---|
| Publication | August 3, 2026 |
| Entry into force | Not specified |
| Challenged regulation | Circular 9/2025, of December 22, by CNMC (amends Circular 2/2019, of November 12) |
| Claimant | I-DE Redes Eléctricas Inteligentes, SAU |
| Judicial body | National Court — Administrative Litigation Chamber, Section 4 |
| Procedure number | 4/190/2026 (ordinary procedure) |
| Deadline to intervene | 9 days from publication in the Official State Gazette (August 3, 2026) |
| Affected regulatory period | 2026-2031 |
| Category | Energy |
The financial remuneration rate that CNMC set for the 2026-2031 regulatory period is already subject to judicial challenge. I-DE Redes Eléctricas Inteligentes, SAU —Iberdrola's distribution subsidiary— has filed an administrative litigation action before the National Court against Circular 9/2025, of December 22, which establishes the methodology and the rate applicable to electricity transmission, system operation and distribution activities, as well as natural gas regasification, transmission and distribution.
CNMC published the service of process on August 3, 2026 so that any company or entity with legitimate interest can intervene in the proceedings as a defendant. The deadline is 9 days from that date. After that deadline, it is no longer possible to join the proceedings.
What does this regulation establish?
CNMC Circular 9/2025 amends Circular 2/2019, of November 12, which was the reference standard for calculating the financial remuneration rate for regulated energy activities in Spain. This rate acts as the "cost of capital" recognized to regulated companies: it determines what financial return they can obtain on their regulated assets.
The new circular updates that methodology and sets the applicable rate for the 2026-2031 regulatory period, which covers the following activities:
- Electricity transmission
- Electricity system operation
- Electricity distribution
- Natural gas regasification
- Natural gas transmission
- Natural gas distribution
I-DE Redes Eléctricas Inteligentes, SAU considers that the set rate is not appropriate and has challenged the circular before the Section 4 of the Administrative Litigation Chamber of the National Court, where it is processed as ordinary procedure 4/190/2026. The resolution of July 24, 2026 orders the publication of the service of process so that other interested parties can join the proceedings.
Economic and operational impact
The financial remuneration rate is one of the most relevant parameters for regulated companies in the energy sector: it directly determines the return that the regulator recognizes on the regulated asset base. A variation of tenths in this rate can mean differences of millions of euros in the annual regulated revenues of a distributor or transporter.
The outcome of the challenge can lead to three scenarios:
- Dismissal of the challenge: Circular 9/2025 is maintained in full and the rate set for 2026-2031 remains unchanged.
- Partial acceptance: The National Court orders CNMC to review some aspect of the methodology or rate calculation, with possible retroactive adjustment.
- Full acceptance: The circular is annulled and CNMC must approve new methodology, with direct impact on regulated revenues across the sector and potentially on network access tariffs paid by consumers.
While the challenge is pending, Circular 9/2025 remains in force and the rate is applied normally. However, affected companies must assess whether their position in the proceedings —as a defendant or as an interested third party— better protects their economic interests.
Who does it affect?
- Electricity distribution companies regulated by CNMC (including I-DE Redes Eléctricas Inteligentes, Endesa Distribución, UFD, E-Distribución, etc.)
- Electricity transmission companies (mainly Red Eléctrica de España / REE)
- Electricity system operators
- Natural gas regasification operators
- Natural gas transmission companies (mainly Enagás)
- Natural gas distribution companies regulated by CNMC
- Legal and financial advisors of the above, who must assess the advisability of intervening
- Large industrial consumers with interest in the evolution of network access tariffs
Practical example
An electricity distribution company —different from I-DE— that operates in several autonomous communities and has a significant regulated asset base receives notification of the service of process published on August 3, 2026.
Its legal and financial team must analyze whether the rate set by Circular 9/2025 also harms its regulated revenues. If it considers that it does, it has 9 days from August 3 to file a motion to intervene before the Section 4 of the Administrative Litigation Chamber of the National Court in procedure 4/190/2026, requesting to be admitted as a defendant.
If it does not act within that deadline, it will lose the opportunity to defend its position directly in the proceedings, although it may follow the outcome of the challenge and its effects from outside. However, if it intervenes, it will be able to submit arguments, provide evidence and appeal the final ruling if it is unfavorable.
What should companies do now?
- Verify whether the Circular 9/2025 rate negatively affects its regulated revenues. Review with the financial and regulatory team the impact of the rate set for 2026-2031 on the company's regulated asset base.
- Assess the advisability of intervening in procedure 4/190/2026. The deadline is 9 days from August 3, 2026. After that deadline, it is not possible to join as a party to the proceedings before the National Court.
- Commission urgent legal analysis. The motion to intervene must be filed before the Section 4 of the Administrative Litigation Chamber of the National Court. It is recommended to have specialized advice in energy regulatory law.
- Monitor the progress of the challenge. Even if it does not intervene, any company in the sector should follow the evolution of the proceedings, as a favorable ruling could modify the rate applicable to the entire sector and alter regulated revenues retroactively.
- Review financial planning 2026-2031. Incorporate into financial models the scenario of possible modification of the financial remuneration rate as a regulatory risk variable.
Frequently asked questions
What is the financial remuneration rate and why does it matter to distributors?
It is the parameter that CNMC sets to determine the return recognized on the regulated assets of electricity transmission and distribution companies. Circular 9/2025 establishes it for the 2026-2031 period, amending Circular 2/2019. A lower rate means lower regulated revenues for distributors and transporters.
Who has filed the challenge and before which body?
I-DE Redes Eléctricas Inteligentes, SAU has filed the administrative litigation action before the National Court, specifically before Section 4 of the Administrative Litigation Chamber. The proceedings are processed as ordinary with number 4/190/2026.
How much time do companies have to intervene in the challenge?
The deadline is 9 days from the publication of the service of process in the Official State Gazette, which took place on August 3, 2026. After that deadline, it is not possible to join the proceedings as a defendant.
What happens if I-DE's challenge succeeds?
If the National Court accepts the challenge, Circular 9/2025 could be annulled in whole or in part, requiring CNMC to review the methodology and/or the financial remuneration rate for 2026-2031. This would have direct impact on the regulated revenues of all companies in the sector and potentially on the network access tariffs paid by consumers.
Does Circular 9/2025 remain in force while the challenge is pending?
Yes. The filing of the administrative litigation action does not automatically suspend the application of Circular 9/2025. The financial remuneration rate set for 2026-2031 is applied normally until there is a final judicial ruling ordering otherwise.
Official source
View complete regulation in official source
Disclaimer: 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-2026-16924