ESRS-XBRL Tagging: The Digital CSRD Reporting Format Explained

As of August 2026

Sustainability reports prepared in accordance with the Corporate Sustainability Reporting Directive (CSRD) must be digitally tagged so that they can be analyzed by machines and later accessed via the European Access Portal (ESAP). This digital tagging is known as XBRL tagging and, for many companies, represents a technical challenge that is often underestimated alongside the actual preparation of the report’s content.

The timeline has been pushed back twice recently: The Omnibus Package has narrowed the scope of the CSRD, and the revised European Sustainability Reporting Standards (ESRS) require a new taxonomy. The disclosure requirement itself is currently suspended. In this article, you’ll learn what XBRL tagging is, how the ESRS taxonomy is structured, and what factors are currently determining the status of the requirement.

What is XBRL tagging, and what is it used for?

XBRL stands for “eXtensible Business Reporting Language” and is an open, XML-based standard that makes financial and sustainability data machine-readable and comparable. During tagging, the information in the report is marked up with elements from a taxonomy—similar to how HTML marks up the content of a website—but specifically designed for financial and sustainability reports. As a result, report content is no longer unstructured plain text but becomes machine-readable.

For the CSRD, EFRAG developed the ESRS-XBRL taxonomy (ESRS Set 1) and submitted it to the European Commission and the European Securities and Markets Authority (ESMA) on August 30, 2024. Important to note: This taxonomy is a proposal, not applicable law. A taxonomy becomes legally binding only once ESMA has developed the technical regulatory standard and the Commission has incorporated it into Delegated Regulation (EU) 2019/815.

The plan is to submit reports in iXBRL (Inline XBRL) format. Unlike the standard XBRL format, iXBRL is not only machine-readable: the tags are embedded in an HTML layout, so that the same report remains readable to humans as well. It is therefore a significantly better reporting format.

The Most Important Facts About ESRS-XBRL Tagging at a Glance

ESRS-XBRL tagging has several unique features that are important for successful reporting:

1. Hierarchical structure. The data points are organized by levels: parent elements containing general information, followed by child elements with more specific details on individual metrics, and below those, further sub-elements with even more specific data or explanations.
2. Modular layout. The taxonomy is divided into modules that reflect the structure of the standards: cross-cutting standards (ESRS 1 and ESRS 2) for general requirements, and thematic standards for the E, S, and G topics.
3. Three types of data points. Narrative disclosure elements consisting of text blocks (descriptions, guidelines, goals), numerical disclosure elements with quantitative data (e.g., emissions, energy consumption, number of employees), and semi-narrative elements such as yes/no answers or predefined options. In the taxonomy for ESRS Set 1, approximately 70% of the data points were narrative; with the revised standards, this proportion decreases significantly.
4. Hypercubes and Dimensions. Dimensions can be used to further break down data, for example, by country, business segment, or greenhouse gas category. There are explicit dimensions with predefined lists (for example, country or greenhouse gas) and typed dimensions for company-specific values (for example, individual policies, targets, or segments). A hypercube defines which combinations of these dimensions are permitted for a data point, thereby maintaining a tabular and unambiguous structure.
5. Handling company-specific information. The taxonomy maps information that goes beyond the standard requirements using standardized dimensions. Whether and to what extent companies may use their own additional elements beyond this will be determined by ESMA’s technical regulatory standard.

What Changes with the Revised ESRS

The 2024 version is now obsolete. On July 3, 2026, the European Commission adopted the revised ESRS as a delegated act. The number of mandatory data points has been reduced by approximately 60%, and the materiality assessment now follows a more top-down approach.

The legislative act has not yet entered into force: Parliament and the Council have a period during which they may either accept the text in its entirety or reject it. Based on current expectations, the revised standards are expected to be published in the Official Journal by November 2026. They are to be applied starting with the 2027 fiscal year, and voluntary early adoption for the 2026 fiscal year is permitted.

For tagging purposes, this means that the ESRS Set 1 taxonomy published in 2024 is no longer the authoritative version. EFRAG is aligning the taxonomy with the revised standards. Only then will the taxonomy undergo the review process at ESMA and the Commission.

When does the requirement for XBRL tagging take effect?

The requirement for digital labeling is tied to the general scope of application of the CSRD, not to a specific date. The Omnibus Package has fundamentally changed this scope of application.

Amending Directive (EU) 2026/470 entered into force on March 18, 2026. Member States must transpose it into national law by March 19, 2027. For fiscal years beginning on or after January 1, 2027, only companies that had an average of more than 1,000 employees during the fiscal year and generated net revenue of more than €450 million are required to report. Separate thresholds apply to companies from third countries: €450 million in net revenue within the EU, as well as a subsidiary or branch with net revenue exceeding €200 million.

When it comes to the schedule, it’s worth making a distinction:

• Companies that were already reporting as part of the first wave will continue to report consistently starting with the 2024 fiscal year, provided they meet the new thresholds. For these companies, there is no new first reporting year.
• Companies newly included or continuing to be included in the second wave will begin with the 2027 fiscal year and publish their reports in 2028.
• Member States may exempt companies that fall outside the scope of this regulation from the reporting requirement for fiscal years between January 1, 2025, and December 31, 2026.

It is also important to note that the German implementation of the CSRD is still pending. Ultimately, national law—not the directive—will apply to your company. For details on the scope of application and timeline, please see our article on the CSRD Implementation Act.

Why No One Is Required to Label Their Products Right Now

Article 2(9) of Directive (EU) 2026/470 replaces the third subparagraph of Article 29d(1) of the Accounting Directive 2013/34/EU. The revised text clarifies that as long as the Commission has not adopted provisions regarding the labeling of sustainability reporting in Delegated Regulation (EU) 2019/815, companies are not required to label their sustainability reporting. The obligation exists in law but is effectively suspended until the Commission takes the necessary technical measures.

There are two caveats:

• Only the award for sustainability reporting is suspended. The existing ESEF requirements for capital market-oriented companies remain unaffected: The management report must still be prepared in XHTML format, and the IFRS consolidated financial statements must still be tagged in accordance with Delegated Regulation (EU) 2019/815.
• The text of the directive does not specify a specific date for the technical update. However, the path forward is clear: ESMA is developing the regulatory technical standard, which the Commission will then incorporate into Delegated Regulation (EU) 2019/815. Since the taxonomy must first be aligned with the revised ESRS, completion is not expected in the near term.

Regardless of the tagging schedule, the substantive audit of sustainability reporting remains in effect, and compliance with the labeling requirement is explicitly part of the scope of the audit once it takes effect. We describe what auditors specifically require in this regard in our article on the audit of sustainability reporting.

Why It’s Worth Preparing Even Though It’s Not Required

XBRL tagging standardizes sustainability reporting and makes it comparable, both for your company and for your stakeholders. Even though the start date has not yet been set, it’s worth preparing early: A well-structured data point catalog with clear sources and responsibilities can be transferred directly into the tagging structure later on. Assigning data points retroactively is significantly more time-consuming.

Specifically, there are three main things that can be done today to prepare: redefine the data points based on the revised ESRS; document the source, system, and responsible role for each data point; and store recurring information in a structured format rather than as plain text.

Do you need assistance with preparing and implementing the ESRS-XBRL taxonomy? Contact us for a no-obligation consultation.

This article provides a professional assessment as of August 2026 and is not a substitute for a legal review in individual cases.