Australia, Belgium, Italy, Kuwait, the Netherlands and Spain have launched or expanded Pillar Two filing frameworks, signalling a major transition from legislative implementation to operational compliance as multinational enterprise groups prepare for the first global minimum tax reporting deadlines in 2026.
Tax authorities across several jurisdictions are accelerating the rollout of compliance systems for the OECD’s Pillar Two global minimum tax regime, with new filing portals, technical specifications, deferrals and reporting procedures now being introduced ahead of the first major deadlines in 2026.
The developments reflect a broader global shift from policy design to administration and enforcement of the OECD’s Global Anti-Base Erosion (GloBE) Rules, which require large multinational enterprise (MNE) groups to pay a minimum effective tax rate of 15% in every jurisdiction where they operate.
Countries are now focusing on the practical mechanics of implementation, including electronic filing systems, data exchange arrangements, notification procedures and transitional relief measures for first-time filers.
Australia opens first Pillar Two lodgments
Australia formally opened lodgments for Pillar Two returns on 5 May 2026, allowing in-scope MNE groups to begin submitting both the GloBE Information Return (GIR) and the combined global and domestic minimum tax return (CGDMTR).
The Australian framework implements the OECD GloBE Rules through both a global minimum tax and a domestic minimum tax mechanism.
Taxpayers may lodge returns through Online services for agents or Online services for business, while GIR submissions must be completed using the online services file transfer facility. Authorities have also issued lodgment instructions and published the CGDMTR form to support compliance.
An automatic 30-day deferral applies to returns originally due on 30 June 2026, providing taxpayers with additional time without requiring formal applications. Longer extensions or future-period deferrals remain available under standard administrative procedures.
The Australian rollout represents one of the clearest examples of tax administrations moving from legislative enactment into active operational compliance under Pillar Two.
Belgium extends filing deadlines
Belgium has opted for a more flexible approach by extending filing deadlines for both the Qualified Domestic Minimum Top-up Tax (QDMTT) and supplementary tax declarations under the Income Inclusion Rule (IIR).
The Federal Public Service Finance announced on 3 April 2026 that companies subject to the Belgian minimum tax rules would receive additional time to comply with the new reporting obligations.
Under the revised timetable, national supplementary tax declarations for fiscal years beginning on or after 31 December 2023 and ending between 1 January 2024 and 30 September 2025 must now be filed by 30 September 2026.
Belgium also aligned various IIR filing deadlines to the same date. Fiscal years starting on or after 1 January 2025 and ending by 31 May 2025, as well as fiscal years beginning between 31 December 2023 and 31 December 2024 and ending by 28 February 2025, will all benefit from the extended 30 September 2026 deadline.
The extensions indicate growing recognition among tax authorities that the initial implementation phase presents significant administrative and data challenges for both taxpayers and governments.
Italy builds detailed reporting infrastructure
Italy has introduced one of the most comprehensive Pillar Two compliance frameworks to date, issuing multiple orders, technical specifications and software tools to facilitate reporting.
The Italian Revenue Agency issued orders on 8 and 9 April 2026 approving the technical specifications, electronic filing procedures and XML schemas for annual global minimum tax returns covering the Income Inclusion Rule (IIR), Undertaxed Profits Rule (UTPR) and Qualified Domestic Minimum Top-up Tax (QDMTT).
The reporting framework applies to multinational and domestic groups with annual revenues exceeding EUR 750 million in at least two of the previous four fiscal years.
Italy’s system requires taxpayers to submit returns electronically through the Entratel or Fisconline services using XML formatting. The filings include both a general section and jurisdiction-specific information necessary to calculate top-up tax liabilities.
Generally, returns must be filed within 15 months after the fiscal year-end, although transition-year filings benefit from an 18-month deadline. Importantly, first submissions cannot be due before 30 June 2026.
Italy has also introduced dedicated software for two separate compliance obligations: the notification form identifying the entity responsible for the GIR, and the global minimum tax declaration itself.
The Revenue Agency confirmed that information collected under the system will be exchanged automatically with other EU Member States and qualifying jurisdictions, with first exchanges scheduled no earlier than 1 December 2026.
The framework stems from Legislative Decree No. 209/2023, which established Italy’s three-part minimum tax regime targeting low-taxed subsidiaries, undertaxed foreign profits and domestic top-up taxes.
Kuwait launches optional advance payment programme
Kuwait has adopted a different compliance strategy by introducing an optional Advance Tax Payment Program for MNE groups subject to the domestic minimum top-up tax.
The initiative, announced through Circular No. (1) of 29 April 2026, applies to the supplementary domestic minimum top-up tax (DMTT) at a 15% rate effective from 1 January 2025.
Participating taxpayers must submit applications and estimated DMTT calculations by 31 May 2026, with payment due in a single instalment by 30 June 2026.
The advance payments will be credited against final liabilities once formal returns are filed, which remain due within 15 months after the end of the relevant tax period.
While participation is voluntary and carries no penalties for non-participation, the Ministry of Finance is offering administrative incentives, including priority treatment for audits, refunds, objections, appeals and tax card renewals.
The programme is expected to apply primarily to the first DMTT reporting cycle and appears designed to facilitate early revenue collection while easing the transition into the new regime.
Netherlands and Spain activate digital reporting systems
The Netherlands and Spain are also entering the operational phase of Pillar Two compliance.
The Dutch Tax and Customs Administration announced that digital filing services for Pillar Two returns will go live from 1 June 2026 under the Minimum Tax Act 2024.
Dutch taxpayers will use separate digital channels depending on the filing type, including Digipoort for the GIR, the Data Portal for GIR notifications, and the My Tax and Customs Administration Business portal for top-up tax returns.
Although GIR filings and notifications are due by 30 June 2026, taxpayers will have until 31 August 2026 to submit top-up tax returns.
Spain, meanwhile, opened its first GIR and notification filing window on 30 April 2026 under Law 7/2024 implementing the EU Minimum Tax Directive.
The Spanish framework forms part of a phased implementation programme that will later incorporate UTPR and QDMTT reporting obligations through forms approved under Ministerial Order HAC/1198/2025.
Together, these developments demonstrate how tax authorities are rapidly constructing the administrative architecture necessary to support the OECD’s global minimum tax system, with 2026 emerging as the first major year of operational Pillar Two compliance worldwide.
