Do tax appeals change in 2026? Key points of the new electronic regulation from 15 January

From 15 January 2026, tax appeals before the economic-administrative courts are governed by a new regulation that strengthens the mandatory use of electronic means for companies and professionals. The regulation introduces standardised electronic forms, formalises online submission of documents and reinforces electronic notifications. For businesses, this requires reviewing digital certificates, notification systems, and deadline controls to avoid procedural issues.

The digitalisation of tax procedures takes a decisive step forward in 2026. From 15 January, a specific regulation on electronic actions in economic-administrative tax appeals comes into force, directly affecting companies, professional firms and tax representatives.

This regulation replaces the framework in force since 2009 and adapts appeal procedures to the current digital environment, in line with Law 39/2015 and the established practice of electronic interaction with the Spanish Tax Agency and the economic-administrative courts.

The new framework is approved by Order HAC/1361/2025, published in the Official State Gazette (BOE), and applies to all actions before the economic-administrative courts from 15 January 2026 onward.

The order specifically regulates the use of electronic means in economic-administrative proceedings and builds on the general principles established in Law 39/2015.

The obligation to interact electronically applies in particular to:
• Legal entities.
• Entities without legal personality.
• Regulated professionals acting as representatives.
• Tax representatives of taxpayers.

For these parties, paper submissions are no longer valid and may lead to requests for correction or procedural risks related to deadlines.

The main change is not only digitalisation itself, but also the formal regulation of how electronic actions must be carried out.

Companies and professionals subject to the obligation must submit electronically:
• Economic-administrative appeals.
• Appeals for annulment and review.
• Statements and pleadings.
• Applications for suspension.
• Responses to requests and corrections.

Using an incorrect submission channel may have significant procedural consequences.

The order approves 16 official electronic forms, replacing the three models previously in use.

These forms cover nearly all possible actions in the procedure and serve as the standard channel of communication with the economic-administrative courts.

Their purpose is to:
• Reduce formal errors.
• Facilitate internal processing.
• Harmonise criteria across different courts.

The regulation reinforces the use of:
• Qualified electronic certificates.
• The Cl@ve system, where applicable.
• Secure verification codes.
• Electronic seals in notifications and decisions.

Proper management of representation is essential, as all actions are carried out in a wholly digital environment.

Notifications are issued electronically, with legal effects triggered by their availability in the electronic mailbox.

This requires companies to:
• Actively monitor electronic notification systems.
• Clearly assign internal responsibility.
• Avoid delayed or missed access.

Lack of awareness of a notification does not prevent its legal effects.

From a substantive perspective, the regulation does not restrict the right to appeal. However, it significantly increases formal and organisational requirements.

The main risks include:
• Incorrect use of electronic forms.
• Expired or invalid digital certificates.
• Improperly registered powers of attorney.
• Insufficient control of electronic notifications.

In many cases, the issue lies not in the merits of the appeal but in procedural compliance.