Executive summary

On 28 September 2026, the Belgian tax authorities announced a further extension of the filing deadlines for several Belgian Pillar Two compliance obligations (see: Extension QDMTT and IIR Return | FOD Financiën and Extension GIR Notification | FOD Financiën). As a result, the filing deadlines for the Belgian Qualified Domestic Minimum Top-up Tax (QDMTT) return, the Income Inclusion Rule (IIR) return and the Global Anti-Base Erosion (GloBE) Information Return notification (GIR notification) have generally been extended to 31 October 2026. No general extension has been granted for the GIR itself.

This additional extension provides in-scope groups with more time to comply with their first Belgian Pillar Two reporting obligations.

Separately, on 10 September 2026, a draft bill was submitted to Parliament to transpose DAC9 into Belgian law and introduce several amendments to the Belgian minimum tax legislation. The draft bill proposes aligning the statutory QDMTT filing deadline, currently due in principle by the end of the eleventh month following the fiscal year-end, with the filing deadlines applicable to the other Pillar Two returns.

QDMTT and IIR return deadlines further extended

Under the current Belgian Pillar Two tax legislation, a QDMTT return must generally be filed by the last day of the eleventh month following the end of the relevant fiscal year. However, given the delayed availability of the Belgian filing framework, the Belgian tax authorities previously granted successive administrative filing extensions.

In their latest communication, the Belgian tax authorities now confirmed that all Belgian QDMTT and IIR returns for which the filing deadline would otherwise fall before 31 October 2026 may now be filed by that date.

Under the Belgian Pillar Two rules, if more than one Belgian group entity is subject to the QDMTT, a designated general representative must be appointed. The Belgian tax authorities clarified that any proactive notification appointing a general representative must be submitted before the relevant QDMTT return is filed. If no explicit appointment is notified, statutory cascade rules apply or the first entity to file the QDMTT return is deemed to hold the role automatically.

GIR notification deadline also moved to 31 October 2026

Under Belgian law, each in-scope Belgian entity is, in principle, required to notify the Belgian tax authorities of the filing entity responsible for submitting the GIR. If a designated Belgian local entity files the notification on behalf of all Belgian group entities, a single notification may suffice for the Belgian group entities concerned.

In principle, in accordance with the administrative guidelines, the GIR notification must generally be submitted no later than the deadline applicable to the corresponding GIR.

The Belgian tax authorities have now also confirmed an extension of the filing deadline for the GIR notification. The deadline for filing the GIR notification is extended until 31 October 2026 for notifications relating to a GIR with a reporting fiscal year that either:

• Begins no earlier than 1 January 2025 and ends no later than 30 June 2025
• Begins on or after 31 December 2023 and no later than 31 December 2024, and ends no later than 31 March 2025

The GIR notification extension applies to notifications relating to GIRs for the first reporting periods covered by the Belgian Pillar Two rules.

Importantly, the extension concerns the GIR notification only. The filing deadline for the GIR itself continues to follow the deadlines provided under the Belgian minimum tax legislation and applicable international filing arrangements.

Draft bill proposes structural alignment of QDMTT filing deadlines

In parallel with these administrative extensions, a draft bill was recently introduced implementing DAC9 and amending various aspects of the Belgian minimum tax legislation.

One of proposed changes concerns the filing deadline for the Belgian QDMTT return. As mentioned, under the current legislation, the QDMTT return is due by the last day of the eleventh month following the fiscal year-end, which creates a mismatch with the filing deadlines applicable to the GIR and the IIR return.

The draft bill would align the QDMTT filing deadline with the deadlines applicable to the other Pillar Two returns. Subject to parliamentary approval, the QDMTT return would generally become due by the last day of the fifteenth month following the fiscal year-end, while the eighteen-month filing deadline applicable to certain first-year filings would be retained.

Implications and next steps

Although the additional extension provides welcome relief, affected groups should continue to advance their Pillar Two compliance deliverables.

Entities that need assistance complying with their obligations under the Belgian Pillar Two legislation or have general Pillar Two-related questions should reach out to knowledgeable tax advisors.