European Single Electronic Format (ESEF)

1. What is the ESEF?

ESEF is a format in which issuers, who are subject to the obligation to disclose their annual financial report in accordance with the Transparency Directive, must prepare their financial statements.

2. What is the legal basis?

In 2013, the Transparency Directive, which defines rules concerning the harmonisation of transparency requirements of issuers, was amended to include, amongst others, a requirement for issuers to prepare their annual financial reports in a single electronic reporting format. 
In this respect, ESMA was mandated to develop regulatory technical standards to specify this electronic reporting format (ESEF RTS).   
The ESEF RTS, published on 29 May 2019 in the form of a Commission Delegated Regulation, requires annual financial reports to be entirely prepared in XHTML, which is both human readable and machine readable, and which can be opened with any standard web browser. 
For detailed information and further guidance, including video tutorials and a ESMA’s Reporting Manual – Preparation of Annual Financial Reports in ESEF format, please see ESMA’s ESEF webpage.

3. When will it apply?

The use of ESEF was initially announced to apply to annual financial reports created for the fiscal years starting from 1 January 2020 onwards. 

However, Member States have been granted the possibility to defer the mandatory application to the annual financial reports for periods beginning on or after 1 January 2021.  

For issuers subject to the Transparency Law1, the 1-year postponement option of the ESEF requirements will be applied in Luxembourg. 

Annual financial reports for the period beginning on or after 1 January 2020 could be filed in ESEF format on a voluntary basis. 

For further details, please see CSSF’s press release.

1Issuers for which Luxembourg is the home Member State pursuant to the law of 11 January 2008 on transparency requirements (Transparency Law).

4. Who is concerned?

Issuers whose securities are admitted to trading on any EEA regulated market and which are subject to the obligation to disclose their annual financial report under the Transparency Directive are concerned. Issuers listed on the Luxembourg Stock Exchange (LuxSE)’s Regulated Market are, as such, within the remit of this obligation to the extent the disclosure obligation applies to them.

5. How will ESEF impact LuxSE’s OAM/FIRST?

Under the Transparency Directive, issuers are required to make regulated information available to the national officially appointed mechanism (OAM) for its central storage. 
LuxSE is the OAM in Luxembourg. 
To assist our clients with ongoing obligations in terms of OAM storage, filing documents with the financial sector regulator and disseminating information to the public, LuxSE offers a multi-functional reporting tool called FIRST – Financial Instruments Reporting Services Tool. 
Due to the introduction of ESEF, if the information contains annual financial reports that qualify as regulated information and refer to a financial year starting from 1 January 2020 onwards, FIRST allows for the submission of XHTML format files or a ZIP as defined by the XBRL specifications. 
If your company produces IFRS consolidated financial statements, Inline XBRL technology should be embedded in the XHTML, allowing the financial information to be readable to the human eye while at the same time being structured and machine readable.  
Please note that with respect to mandatory submissions of annual financial reports:

    • Either XHTML format files or a ZIP reporting package containing a single XHTML format file (but not both) is allowed for storage
    • A PDF format file is still accepted, provided that the XHTML format file is also stored (i.e. you can still file your annual financial reports using a PDF format provided that you also file your annual financial reports under the XHTML format).

6. Do you need further information?

Should you have any questions or need assistance, please contact us at

Last update on 18 October 2022


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