Authors: Yannick Cools, Joke Gysens & Sarah Keulemans

As of 1 January 2024 (financial years starting from 31/12/2023), the minimum tax for multinationals and large domestic groups (Pillar II) has entered into force. Groups with a consolidated turnover of at least EUR 750 million in at least two of the four preceding financial years must, since then, pay at least 15% tax. The minimum rate of 15% is achieved via three levy mechanisms: the Qualified Domestic Minimum Top-up Tax (QDMTT), the Qualified Income Inclusion Rule (IIR), and the Qualified Undertaxed Profits Rule (UTPR).

In Belgium, the QDMTT return must be filed by the last day of the eleventh month following the end of the financial year. For groups with a financial year ending on 31 December 2024, this means the first return should be filed no later than 30 November 2025. The Belgian tax administration had already granted an extension for the first QDMTT return to 30 June 2026.

On 3 April 2026, the Belgian tax administration published a new update regarding the domestic top-up tax return. An additional extension is now granted for filing the domestic top-up tax return until 30 September 2026.

This extension applies to groups whose first filing period ends between 1 January 2024 and at the latest on 30 September 2025.

Please note: this extension only applies to the first filing period. For subsequent financial years, the original term of eleven months after the end of the financial year remains in effect. E.g. the financial year closing per 31.12.2025 will have a tax return obligation ultimately per 30.11.2026.

The IIR-tax return deadline has equally been extended until 30.09.2026.

This means that for the submission of both the Belgian QDMTT and IIR returns, where the statutory deadline for submission falls before 30 September 2026, an extension is granted until 30 September 2026.

The GloBE Information Return (GIR), on the other hand, seems to uphold the initial deadline of 30.06.2026.

Why an extension?

The final version of the QDMTT return has not yet been published. In this context, the Belgian administration has therefore decided to grant another extension.

In addition, the administration’s announcement states that practical guidelines and technical documentation on the filing procedure will be communicated at a later date.

Despite the extension, we advise taxpayers to continue preparing and gathering the necessary information so that the filing process can proceed smoothly later on. Groups that fall under the permanent and temporary safe harbours are also required to file a QDMTT return in Belgium.

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