For the record: The Pillar 2 rules under the EU Directive (i.e. legislation concerning the 15% minimum tax) apply, subject to certain exceptions, to multinational groups (and large domestic groups) with consolidated revenue of EUR 750 million or more in at least two of the four preceding financial years.
In respect of the Belgian Pillar 2 compliance formalities to be fulfilled, the Belgian Tax Authorities have announced a further administrative extension for both the Qualified Domestic Minimum Top-up Tax (QDMTT) return and the Income Inclusion Rule (IIR) top-up tax return. Any filing deadline that would otherwise fall before 30 September 2026 is now deferred to that date. For the QDMTT return, this is already the second extension of the original filing deadline, set for 30 November 2025.
This extra time will be welcome news for groups preparing their first Belgian Pillar Two compliance filings. At the same time, the public consultation on the draft IIR return and the publication of the draft QDMTT return template show that Belgian compliance is moving into a more operational phase.
What are the standard deadlines?
Under Belgian minimum taxation rules, the QDMTT return is in principle due on the last day of the 11th month following the end of the fiscal year. The IIR top-up tax return follows the timing of the GloBE Information Return and is generally due on the last day of the 15th month following the end of the fiscal year. For the first filing period, the latter deadline is extended to the last day of the 18th month for fiscal years beginning no later than 31 December 2024.
Which periods are covered?
The administrative tolerance applies to all QDMTT and IIR top-up tax return deadlines falling before 30 September 2026.
For the QDMTT return, this means fiscal years beginning on or after 31 December 2023 and ending between 1 January 2024 and 30 September 2025.
For the IIR top-up tax return, the extension applies to fiscal years that:
- begin between 31 December 2023 and 31 December 2024 and end no later than 28 February 2025; or
- begin on or after 1 January 2025 and end no later than 31 May 2025.
Why does this matter for your business?
The deadline extension gives multinational groups more breathing space, but it should not be seen as a reason to postpone preparation. For many businesses, the real challenge will not be the filing itself, but identifying the right data points, aligning calculations and building a workable internal process.
The message from the Belgian Tax Authorities is clear: more time has been granted, but compliance expectations are becoming more concrete. Further guidance and technical details on the filing process are still expected, so now is the right time to get organised.
Time for action
Groups within scope should use this additional time to:
- confirm which Belgian entities and fiscal periods are affected;
- map the data needed for QDMTT and IIR reporting;
- test the calculation methodology and supporting documentation; and
- align Belgian filing obligations with their broader Pillar Two compliance approach.
How can HLB help?
HLB can support you with the practical rollout of Belgian Pillar Two compliance, including registration, data mapping, top-up tax calculations and filing readiness. We can also help you coordinate Belgian requir
