The treatment under the Pillar Two GloBE rules depends on whether there is an increase or decrease in the covered taxes and the amount of the adjustment.
Prior year increases in covered taxes are treated as an adjustment to the current year’s covered taxes under Article 4.6.1 of the OECD Model Rules.
Prior year decreases in covered taxes require a recalculation of the ETR and top-up tax in the previous year that the adjustment relates to. However, where a reduction is less than 1 million euros the MNE can elect for this to be adjusted in the current year.
The carryback of a local tax loss that gave rise to a refund of tax or other reduction in tax payable in the previous year would also be treated as a decrease in covered taxes.
However, there are special provisions for deferred tax that apply to loss carrybacks, for more information, see Deferred Tax.
These rules mirror the treatment for prior year adjustments to Pillar Two GloBE income and ensure that both the income and tax are aligned in the same fiscal year for the ETR calculation.
A change in domestic tax rates is not taken into account in the current year but could have deferred tax implications.
Where there is a reduction to the domestic tax rate below the 15% global minimum rate, deferred tax in a previous year may need to be recomputed under Article 4.6.2 of the OECD Model Rules.
For instance, if a deferred tax liability of 1 million euros is created in year 1 at a corporate income tax rate of 20%, this would result in adjusted covered tax of 200,000 euros. In year 2, the domestic tax rate is reduced to 10%.
The deferred tax liability in year 1 would need to be recomputed based on the 10% rate, with the adjusted covered tax being 100,000 euros. Additional top-up tax of 100,000 euros would therefore be due.
In this case, the amount is not material and would be due in year 2. If it was material, the ETR and top-up tax in year 1 would be amended.
Where there is an increase in the domestic tax rate, this could require an adjustment to the deferred tax expense in a previous year under Article 4.6.3 of the OECD Model Rules. In general, an increase in the rate that applies to a deferred tax liability is disregarded until the liability is unwound and the tax is paid.
The additional tax payable is then treated as an increase in covered taxes in the previous year.
Just as for deferred tax that is not unwound, a recapture rule applies to a current tax expense that is claimed as adjusted covered tax and is not paid under Article 4.6.4 of the OECD Model Rules. This applies where the unpaid tax is more than 1 million euros.
Unlike deferred tax, a three-year recapture rule applies (it is five-years for deferred tax).
A guide to Italy’s three-track Pillar Two process: the reporting-entity notification, the DAC9/GIR (Comunicazione Rilevante), and the domestic GloBE Return (Dichiarazione fiscale Globe) with related F24 payments.
A guide to Australia’s Pillar Two filing. It covers the separate local GIR XML filing, the foreign lodgement notification, and the Combined Global and Domestic Minimum Tax Return (CGDMTR), including the Australian IIR/UTPR tax return and Australian DMT tax return. It also flags the main ATO validation rules and the software / API points that matter if you are building or testing a filing process.
A guide to Spain’s three-part Pillar Two workflow: model 240 (group/filing notification), model 241 (GIR-DAC9 information return), and model 242 (top-up tax self-assessment).
On April 7, the Swiss Federal Tax Administration issued Communication-031-E-2026-f and Communication-030-E-2026-f to apply the OECD January 2025 and January 2026 Administrative Guidance
On April 8, 2026, Germany issued a Draft Regulation which included a list of jurisdictions with qualifying status for the purposes of the IIR, UTPR, QDMTT and the QDMTT Safe Harbour.
On April 8, 2026, the Turkish Revenue Administration published draft versions of its Pillar Two Tax Returns/Notifications.
On April 3, 2026, Liechtenstein enacted an amendment to its Pillar Two Regulation (LGBl. 2026 Nr. 114). This includes amendments to the Pillar Two regime including providing for aspects of the January 2026 Side-by-Side tax package.
A guide to Vietnam’s Pillar Two compliance flow: the reporting-entity notification, special tax registration, the GIR information package embedded in the Vietnamese filing package, and the QDMTT and IIR return packages filed through the tax e-filing system.
This guide focuses on Austria’s GIR filing architecture as published by the Austrian Federal Ministry of Finance (BMF): access to FinanzOnline, filing channels, the Austrian national XML overlay on top of the OECD GIR, correction mechanics, and transport/protocol handling for implementation.
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