Pillar 2: Belgian tax filing deadlines are fast approaching – deadline 30 September 2026

With the end of summer in sight, the first Belgian Pillar 2 reporting obligations are also drawing nearer. For many multinational groups falling within the scope of the Belgian Pillar 2 legislation, 30 September 2026 is a crucial deadline. The requirements include:

• Qualified domestic minimum top-up tax (QDMTT) returns for reporting years that:
  • commence on 31 December 2023 or later, and
  • end no earlier than 1 January 2024 and no later than 30 September 2025.
• IIR top-up tax returns for reporting years that:
  • commence no earlier than 1 January 2025 and end no later than 31 May 2025, or
  • commence on or after 31 December 2023 and no later than 31 December 2024, and end no later than 28 February 2025.
• GIR notification relating to reporting years that:
  • commence between 31 December 2023 and 31 December 2024 and end no later than 28 February 2025; or
  • commence no earlier than 1 January 2025 and end no later than 31 May 2025.

Belgian QDMTT return

Belgian group entities falling within the scope of the Pillar 2 rules must, in principle, file a Belgian qualified domestic minimum top-up tax (QDMTT) return or a domestic top-up tax return, even if no top-up tax is ultimately payable. Even where a transitional or permanent safe harbour applies, the obligation to file a return still applies.

Belgian IIR return

As well as the QDMTT return, certain groups may also be required to submit a Belgian return relating to the income inclusion rule (IIR) top-up tax. This is the case where, under the Pillar 2 rules, Belgium is authorised to raise a supplementary tax in respect of low-taxed foreign group entities.

General representative notification

Where a group comprises several Belgian group entities, a single Belgian entity may be appointed as the general representative for the Belgian QDMTT and UTPR (undertaxed profit rule) obligations. The Belgian tax authorities must be informed in advance of this appointment by means of a separate notification. The notification must be submitted before the Belgian QDMTT return and, where applicable, the Belgian UTPR return are filed (in principle, 15 months after the end of the financial year).

GIR notification

In addition, a GIR notification must be submitted for the relevant reporting period. Its purpose is to inform the Belgian tax authorities about the group entity responsible for filing the GIR (global information return), as well as the jurisdiction in which this return will be filed.

Where there are several Belgian group entities, a single notification may be submitted on behalf of all Belgian group entities.

Practical points to bear in mind

Belgian Pillar 2 returns and notifications must be prepared in XML format and submitted electronically via MyMinfin. In addition, the Belgian tax authorities have recently introduced a specific Pillar 2 mandate that companies can use to authorise their advisers to meet these compliance obligations on their behalf. Until 31 December 2026, the BIZTAX mandate may also still be used to submit these returns. From 1 January 2027, the Pillar 2 mandate will be required.

Preparing in good time remains essential

Although many groups have already carried out an impact assessment, experience shows that preparing for the Belgian Pillar 2 requirements often takes longer than expected. Gathering the necessary group information, identifying the correct reporting entities and assessing any safe harbour arrangements require thorough preparation. We recommend that you review your current compliance plan in good time and check what still needs to be done.

Grant Thornton can assist you with the preparation, review and submission of the Belgian QDMTT return, the IIR return, the general representative notification and the GIR notification.

Get in touch with us to discuss how we can provide you with efficient support regarding the Belgian Pillar 2 formalities.