What Changes with the 2025 Update to the ESEF Format for Listed Companies

The Commission Delegated Regulation (EU) 2026/283, published on 18 March 2026 in the Official Journal of the European Union, introduces significant changes to the taxonomy of the European Single Electronic Format (ESEF) that directly affect all companies listed on regulated markets in the EU. If your company publishes annual financial reports with XBRL tagging, this update concerns you and you must act before submitting reports for the 2025 financial year.

This regulation amends Delegated Regulation (EU) 2019/815, which established the original ESEF framework. This is not an entirely new regulation, but rather a periodic technical update to keep the taxonomy aligned with the latest versions of the International Financial Reporting Standards (IFRS).

What does this regulation establish?

Delegated Regulation (EU) 2026/283 updates the ESEF taxonomy applicable to financial years beginning in 2025. In practical terms, this means that the set of XBRL tags and markup elements that listed companies use to tag their financial statements has been reviewed and expanded to reflect the most recent changes to IFRS.

The key technical aspects covered by the regulation are:

• Update of XBRL tags: New tags are incorporated and existing ones are modified to align with the latest IFRS amendments.
• New markup elements: Additional elements are introduced that companies will need to apply when tagging their financial statements.
• Temporal scope: The changes apply to financial reports for financial years beginning in 2025.

It is important to note that this update directly amends Delegated Regulation (EU) 2019/815, which is the base regulation for ESEF. Therefore, companies that were already complying with the ESEF format must verify whether their current systems are compatible with the new taxonomy, and not assume that the previous configuration remains valid.

Who is affected and how?

This regulation affects all companies listed on regulated markets in the European Union that are required to submit their annual financial reports in ESEF format with XBRL tagging. In Spain, this includes listed companies supervised by the CNMV that prepare their accounts under IFRS.

Some examples of how this has a practical impact:

• The finance team will need to ensure that the financial statements for the 2025 financial year are tagged in accordance with the new taxonomy, and not with the previous version.
• The audit team will need to verify that the XBRL tagging applied meets the updated requirements before issuing their report.
• The technology or systems team will need to update or configure financial reporting software tools to ensure compatibility with the 2025 taxonomy.
• In the event of non-compliance, national securities regulators — such as the CNMV in Spain — may impose penalties. For details on applicable penalties, refer to the original regulation and your national regulator.

What do you need to do to comply?

Coordination between the finance, audit and technology departments is essential to meet the deadline. Below are the action steps that follow directly from the regulation:

• Review the new ESEF 2025 taxonomy: Analyse the changes in tags and markup elements compared to the previous version to identify which aspects specifically affect your company.
• Update your financial reporting software: Check with your XBRL tools provider that the new taxonomy is already available and implemented on the platform you use.
• Coordinate internal teams: Establish a joint working group between finance, audit and technology to manage the transition in an orderly and error-free manner.
• Review financial statements before tagging: Ensure that the preparation of the 2025 financial statements takes the new markup elements into account from the outset, not only at the final tagging stage.
• Plan ahead before publication: Annual reports for the 2025 financial year must comply with the new taxonomy. Plan the implementation well in advance to avoid delays in publication.
• Consult the original regulation for specific details: For specific technical aspects, additional deadlines or specific interpretations, refer directly to the text of Delegated Regulation (EU) 2026/283 and, if necessary, to a specialist adviser.

Official source

📄 View full regulation at the official source

Disclaimer: This article is for informational purposes only and does not constitute legal advice. For specific decisions regarding your situation, please consult a qualified professional. Original source: https://eur-lex.europa.eu/./legal-content/AUTO/?uri=OJ:L_202600283