Belgian Pillar 2 compliance enters operational phase

Following the introduction of the Belgian Pillar 2 (the global minimum tax) legislation and the publication of Circular 2025/C/68 (see our previous Tax Insights), the Belgian tax authorities have now entered the next phase of the Belgian Pillar 2 compliance framework. 

While the model forms and explanatory guidance for the Belgian Pillar 2 QDMTT (Qualified Domestic Minimum Top-up Tax) and IIR (Income Inclusion Rule) returns had already been made available earlier, the MyMinfin platform became operational on 1 July 2026, allowing taxpayers to effectively submit their Pillar 2 filings electronically. 

At the same time, the Belgian tax authorities introduced the practical framework for two new compliance obligations: the notification of the General Representative and the GloBE Information Return (GIR) filing entity notification. For both obligations, the relevant guidance and XML tools have now been made available, allowing taxpayers to submit these notifications immediately via MyMinfin. 

For multinational enterprise (MNE) groups and large domestic groups within the scope of Pillar 2, these developments mark the practical start of the Belgian filing process. 
 

DOMESTIC TOP-UP TAX (QDMTT) RETURN

The Belgian tax authorities have activated the electronic filing of the Qualified Domestic Minimum Top-up Tax (QDMTT) return through MyMinfin.

The QDMTT return must be submitted electronically by uploading an XML file generated using the XML tool made available by the Belgian tax authorities.

The filing guidance confirms that:

• where only one Belgian constituent entity is subject to the domestic top-up tax, that entity files the return in its own name;
• where several Belgian constituent entities are involved, a designated General Representative files one joint Belgian return on behalf of all Belgian entities.

The statutory filing deadline remains the last day of the eleventh month following the end of the reporting year. However, the previously announced administrative extension remains applicable. For reporting years beginning on or after 31 December 2023 and ending no later than 31 October 2025, the filing deadline is extended until 31 October 2026.

Groups should also note that, for a financial year ending on 31 December 2025, the QDMTT return for financial year 2025 remains due by 30 November 2026. As a result, many groups will face two Belgian QDMTT filing obligations during the second half of 2026.

In addition, the Belgian tax authorities have updated certain parts of the explanatory guidance accompanying the QDMTT return, providing further practical clarifications on the completion of specific sections of the return.

INCOME INCLUSION RULE (IIR) RETURN

The electronic filing of the Belgian Income Inclusion Rule (IIR) return is now equally available through MyMinfin.

Similar to the QDMTT return, the filing is performed via XML upload. The statutory filing deadlines remain those provided by the Pillar 2 legislation, while the transitional administrative extensions previously announced continue to apply for the first filing periods.

APPOINTMENT OF A GENERAL REPRESENTATIVE

One of the most important practical developments concerns the introduction of the General Representative notification.

Where multiple Belgian constituent entities belong to the same in-scope group, one Belgian constituent entity may be designated as General Representative. This representative is responsible for filing the Belgian QDMTT return on behalf of all Belgian constituent entities.

The appointment must now be notified electronically through MyMinfin using the dedicated notification form.

This electronic notification also appears to replace the practical approach that was previously applied during the initial Pillar 2 notification process. At that time, where multiple Belgian constituent entities formed part of the same group, the Belgian tax authorities requested that a paper mandate signed by all Belgian constituent entities be submitted to appoint the filing entity. The new electronic General Representative notification now appears to fulfil this function in a more streamlined and digital manner.

GLOBE INFORMATION RETURN (GIR) FILING ENTITY NOTIFICATION

Another important new compliance obligation concerns the notification of the GIR filing entity.

Under the Belgian Pillar 2 legislation, every Belgian constituent entity is in principle required to notify the Belgian tax authorities which group entity will submit the GloBE Information Return for the group.

Where several Belgian constituent entities belong to the same group, one Belgian entity may be designated to submit this notification on behalf of all Belgian constituent entities, meaning that only one notification is required per Belgian group.

The notification must be submitted electronically via MyMinfin using the dedicated GIR module and an XML file.

For GIR notifications relating to reporting fiscal years that:

• start between 31 December 2023 and 31 December 2024 and end no later than 31 March 2025; or
• start no earlier than 1 January 2025 and end no later than 30 June 2025,

the notification must be filed by 31 October 2026 at the latest.

For other reporting fiscal years, the applicable filing deadline should be assessed separately.

PRACTICAL CONSIDERATIONS

With the MyMinfin platform now operational and the various notification procedures available, Belgian Pillar 2 compliance has become fully operational in practice.

Groups should therefore ensure that:

• the appropriate Belgian filing entity and General Representative have been identified;
• the GIR filing entity has been determined;
• sufficient time is available to prepare the XML files and complete the required filings before the 31 October 2026 deadline.

HOW RSM BELGIUM CAN ASSIST

RSM Belgium assists multinational groups throughout the Belgian Pillar 2 compliance process, including:

• reviewing the availability of transitional safe harbours;
• preparing and filing the Belgian QDMTT and IIR returns;
• assisting with the appointment and notification of the General Representative;
• preparing and submitting the GIR filing entity notification;
• supporting the practical MyMinfin filing process and reviewing XML files.

If you would like to discuss the impact of these developments on your group or require assistance with your Belgian Pillar 2 obligations, our specialists are happy to assist. Please contact tax@rsmbelgium.be.