iXBRL, XBRL or Excel: which format each European insurance supervisor accepts

Every few months someone on a reporting team asks whether the supervisor would take the quarterly package as a spreadsheet, or whether the iXBRL file the finance team already produces for the annual report could do double duty. The short answer is no on both counts. The long answer is more useful, because the formats overlap at the edges, and that is where filings go wrong.

This article explains what iXBRL is and where it is mandatory, why Solvency II, IORP II and Solvency UK use XBRL as XML instead, and where Excel still has a place. Then a table of twelve supervisors, the format each accepts and the portal it runs, each row checked on the supervisor’s own site, a note on xBRL-CSV, and a decision guide for a group that files in several countries. The last section shows how the XBRL tools from SolvencyTool handle the differences.

iXBRL: what it is and where it is mandatory

Inline XBRL, or iXBRL, embeds XBRL tags inside an XHTML document. The file opens in a browser as a formatted report, and a parser extracts the tagged facts from the mark-up, so one document serves both a human reader and a database. It was designed for financial statements, where narrative and numbers stay together.

Three regimes require it. Under ESEF, ESMA requires every annual financial report of an issuer on an EU regulated market to be prepared in XHTML, with the IFRS consolidated financial statements marked up in Inline XBRL using the ESEF taxonomy; the notes have been block tagged since financial years starting on 1 January 2022. An insurance group with listed shares or bonds files it with the officially appointed mechanism of its home member state, not with the insurance supervisor. In the United Kingdom, HMRC has required the computations of an online Company Tax Return in iXBRL, and for most companies the accounts too, for accounting periods ending on or after 1 April 2010. Companies House follows: all accounts filings made on or after 1 April 2028 must be filed by commercial software in iXBRL, and the web and paper routes close for accounts on that date; the package was moved from April 2027.

None of these files can go to a Solvency II portal or to BEEDS. Prudential templates feed a supervisory database, the human readable layer adds nothing, and the taxonomies differ, so the portal rejects an iXBRL file at the schema check. The XBRL explainer covers the underlying taxonomies and instances.

XBRL as XML: Solvency II, IORP II and Solvency UK

The prudential instance is an XML file with a schema reference to a taxonomy entry point, contexts, units and one element per fact. Nobody reads it without software, and the recipient is a database.

Solvency II reporting under Directive 2009/138/EC is collected by the national competent authority and forwarded to EIOPA. EIOPA’s DPM and XBRL page states that DPM methodology and XBRL are the standard for data submission between EIOPA and the national authorities, and each taxonomy package it publishes, 2.8.2 through the annual 2026 reference date and 2.10.0 from Q1 2027, defines XML instances. The insurer uploads one instance per entry point and reference date to the national portal, which runs the EIOPA rules plus its own checks. Which templates fall into each package is set out in the Solvency II QRT list. IORP II reporting works the same way with EIOPA’s Pension Funds taxonomy, version 2.9.0 since the Q1 2025 reference date, as described in our guide to IORP II reporting.

The national add-ons follow the EIOPA format. The Central Bank of Ireland states that the only acceptable format for its National Specific Templates is XBRL, on its own extension of the EIOPA taxonomy, currently NST taxonomy 1.7.0 of December 2024. The ACPR requires the French national specific states in XBRL on an ACPR taxonomy. DNB publishes a separate Verzekeraars Nationale Staten taxonomy, version 3.1.0 of 11 May 2026, for the Dutch national statements.

Solvency UK is XBRL on a different dictionary. The PRA expects all Solvency II QRT and Bank of England Insurance data in XBRL built on the Bank of England Insurance Taxonomy, submitted through BEEDS, which rejects an instance that references any other taxonomy. The Solvency UK versus Solvency II article covers the template differences.

Where Excel still appears

Excel is not an XBRL syntax, but spreadsheets survive in four places.

Direct entry into national forms. FIONA Online, the joint system of Danmarks Nationalbank and the Danish Finanstilsynet, lets a filer enter data directly, copy it from an Excel sheet or upload a file, but only for the national schemas; the Solvency II package goes through FIONA as an XBRL instance. IVASS’s Solvency II FAQ names XBRL upload as the method, with cell by cell entry in the portal as the alternative.

Portal side conversion. The Gibraltar Financial Services Commission gives firms an Invoke e-Filing portal in which templates are completed online or uploaded as spreadsheets; the portal then builds the single XBRL instance the EIOPA taxonomy requires and runs the assertions.

Feedback and supporting files. The CAA in Luxembourg returns XBRL validation feedback as text, XML or xlsx files. Several supervisors publish their additional validation rules as spreadsheets; the BaFin validation list in our local regulations library is one; the local regulations page collects the rest.

Narrative and pre-application data. The RSR, SFCR and ORSA are documents, not templates. BaFin takes them as PDF through the same MVP procedure as the XBRL package, and the ACPR asks for them in other computer readable formats. Data requested before an internal model or transitional measure application is agreed case by case and often arrives as a spreadsheet.

Twelve supervisors: format and portal

Each row was checked on the supervisor’s own site in September 2026. Format refers to the quantitative Solvency II or Solvency UK package.

The format column is uniform: twelve supervisors, one syntax. The variation is in the portals, the packaging rules and the national validation sets that run after the EIOPA rules. The portals also keep moving, Norway during 2026, Sweden in 2021, so a process that stops at a validated instance ages better than one that hard-codes a portal’s upload mechanics.

xBRL-CSV and the Open Information Model

XBRL International’s Open Information Model defines the meaning of an XBRL report independently of syntax and specifies three interchangeable syntaxes: xBRL-XML, xBRL-JSON and xBRL-CSV. In xBRL-CSV the facts sit in CSV tables, one row per data point, with a JSON metadata file that ties the columns to the taxonomy. For the table shaped datasets supervisors collect, the CSV form is far smaller than the XML.

Banking has moved. The EBA’s plan for DPM 2.0 rebuilt its data dictionary from reporting framework 4.0 and set xBRL-CSV as the only format it will receive once the transition completes; the EBA’s FAQ on reporting innovations records that the mandatory date moved from the December 2025 reference date to March 2026, and DNB has told banks that xBRL-XML will no longer be accepted for those frameworks afterwards.

Insurance is on a slower track. EIOPA’s plan for reporting taxonomy releases of 31 May 2024 says EIOPA is exploring CSV files as an additional, non-mandatory format, that adequate support from XBRL validation engines is a prerequisite, and that the timeline is not defined. Taxonomy 2.10.0 for Q1 2027 is still published for XML instances. One national signal is worth watching: DNB ships both XML and CSV sample instances with its Nationale Staten taxonomy 3.1.0. The Bank of England chose xBRL-XML for BEEDS, and we found no published plan to change the insurance collection.

The practical reading for 2026 and 2027: build and validate XML instances, keep the mapping layer independent of syntax, and expect any switch to be announced per authority with parallel running.

A decision guide for a group filing in several countries

A group with solo entities in Ireland, Luxembourg and Germany, a UK subsidiary and a listed parent has five filing obligations. Four questions sort them out.

Which taxonomy? EU solo entities and the EU group file on the EIOPA Solvency II taxonomy; the UK subsidiary on the Bank of England Insurance Taxonomy; the parent’s annual report on the ESEF taxonomy. Three dictionaries, one source of data.

Which national add-ons? Ireland adds NSTs in XBRL; Luxembourg adds its naming convention and zip packaging; Germany adds its own validations and takes narrative reports as PDF. The add-ons are still XBRL, so they belong in the same validation run as the EIOPA rules, not in a spreadsheet side process.

Which portal, and who holds the credentials? Each portal issues its own accounts, and BEEDS routes through a principal user nominated by the chief executive. Keep an owner and a deputy for each.

Which taxonomy version applies to each reference date? The annual 2026 EU package runs on 2.8.2 and the Q1 2027 package on 2.10.0, and the Bank of England runs its own calendar. Software that holds both and picks the entry point from the reference date avoids the most common rejection, an instance on the wrong release.

With those answered, the group has one mapping, three instance generators and one validation stage that knows every national rule set. Excel stays the review surface; iXBRL stays with the finance team for the annual report and the UK accounts.

Where this lands in the software

QRT Tool produces the EIOPA instance for each solo entity and the group, BOE Tool, the Bank of England XBRL reporting software, produces the Solvency UK instance on the Bank’s taxonomy, and IORP Tool covers pension funds on the EIOPA pension taxonomy. All three share the same import layer, so databases, Excel and CSV sources are mapped once and reused every quarter. Validation runs against the taxonomy assertions, the EIOPA or Bank of England filing rules and, where the authority publishes them, the national specific checks, with resolvers that correct recurring errors before upload. Multi entity accounts hold the group’s legal entities under one login, and the output is a validated instance ready for whichever portal the supervisor runs.