Several important Belgian Pillar 2 compliance developments have been announced in recent days. Most notably, Royal Decrees published in the Belgian Official Gazette confirm the final return forms for the Belgian Qualified Domestic Minimum Top-up Tax (QDMTT) for assessment year 2025 and the Income Inclusion Rule (IIR) top-up tax for assessment years 2024 and 2025.
In addition, the Belgian tax authorities have extended the filing deadline for the GIR Notification. This extension does not apply to any GloBE Information Return (GIR) that must be filed in Belgium.
Below is an overview of the main updates:
Belgian QDMTT return forms
On 15 June 2026, a Royal Decree was published establishing the Belgian QDMTT return form for assessment year 2025. This form applies to fiscal years ended on 31 December 2024, or during 2025 before 31 December 2025.
As a reminder, the Belgian QDMTT return form for assessment year 2024, applicable to fiscal years ended on 31 December 2023 or during 2024 before 31 December 2024, was published on 1 June 2026.
The final forms do not materially differ from the latest draft versions published earlier this year. There are also no significant differences between the forms for assessment years 2024 and 2025. We refer to our previous newsflash for further information on the content of the Belgian QDMTT return.
As a reminder, when the legal deadline of 11 months after fiscal year-end falls before 30 September 2026, an exceptional general extension was granted until 30 September 2026 for filing the Belgian QDMTT return. We refer to our newsflash in this respect.
IIR Top-up tax return forms
Two additional Royal Decrees were published on 15 June 2026, establishing the IIR top-up tax return forms for assessment years 2024 and 2025.
The final forms do not materially differ from the latest draft versions published on 19 March 2026 for public consultation. There are also no significant differences between the forms for assessment years 2024 and 2025. We refer to our previous newsflash for further information on the content of the IIR top-up tax return.
As a reminder, each taxpayer liable for IIR top-up tax must file its own return, meaning there may be multiple IIR Top-up tax returns for a single Pillar 2 in-scope group. Note that when the legal deadline of 18 months after the first fiscal year-end falls before 30 September 2026, an exceptional general extension was granted until 30 September 2026 for filing the IIR Top-up tax return. We refer to our newsflash in this respect.
GIR Notification
On 12 June 2026, the Belgian tax authorities announced a general extension of the filing deadline for the GIR Notification. For assessment years 2024 and 2025, the notification must be filed by 30 September 2026. The Belgian GIR Notification form itself has not yet been published.
Although the tax authorities have not expressly confirmed the scope of this extension, we expect it to apply to groups with a fiscal year ended on or before 31 March 2025. For groups with a fiscal year ended after that date but before 31 December 2025, the statutory Belgian deadline would in principle fall after 30 September 2026, as the GIR Notification must generally be filed within 18 months after the end of the first fiscal year in scope of Pillar 2.
Importantly, this extension applies to the GIR Notification only. It does not apply to any GloBE Information Return (GIR) that is required to be filed in Belgium. For a fiscal year ended on 31 December 2024, the Belgian GIR filing deadline therefore remains 30 June 2026.
Filing on MyMinfin
The above Belgian Pillar 2 compliance filings are expected to be submitted in XML format through the Biztax mandate on the MyMinfin portal of the Belgian (designated) filing entity. As of today, the filing platform is not yet open.
However, in the publication dated 12 June 2026 announcing the extension of the GIR Notification deadline, the Belgian tax authorities stated that the system for filing the GIR Notification is scheduled to open on 1 July 2026. Practical details on how to submit the notification will be communicated when the portal opens.
Finally, on 4 June 2026, the Belgian tax authorities indicated that a simulation environment for the GIR had become available on MyMinfin. Groups can use this environment to test GIR files intended to be submitted in Belgium. This testing environment provides an opportunity to validate the technical format and accuracy of GIR files before the official filing window opens, particularly given the approaching 30 June 2026 deadline. Note that the Belgian tax authorities are not expected to release a XML conversion tool, so groups will need to take care of the conversion internally or via a separate tool, like PwC’s Pillar 2 Engine.
How can PwC help?
Now that the final QDMTT and IIR top-up tax return forms have been officially published, groups should reassess the data and documentation already prepared and identify any remaining gaps. If your group has not yet started the data collection process for the QDMTT and IIR returns, we strongly encourage you to do so as soon as possible, ideally before the summer holiday period and the peak season for corporate income tax filings place additional pressure on internal resources.
Lastly, the Belgian Pillar 2 identification number is expected to be a mandatory field in all Belgian Pillar 2 compliance deliverable. We therefore strongly recommend to ensure this was submitted and that the group number was duly received prior to the filing of any Belgian Pillar 2 return. Please also refer to our newsflash in this respect.
We would be pleased to support you with any Pillar 2 compliance deliverable. Please do not hesitate to reach out to your usual PwC contact or contact Pieter Deré, Koen De Grave or Maxim Allart.
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