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).
On August 8, 2026, Mauritius issued its QDMTT regulations to implement its QDMTT.
On 3 August 2026, Korea’s Ministry of Finance and Economy released its 2026 Tax Reform Proposal. Among its international tax measures are proposed amendments intended to implement significant elements of the OECD/G20 Inclusive Framework’s January 2026 Pillar Two Side-by-Side Package.
Decision No. 12 of 2026 introduces a seven-month registration period, transitional deadlines and a five-year notification regime for UAE entities within the domestic minimum top-up tax framework.
Qatar’s General Tax Authority (GTA) activated its Global and Domestic Minimum Tax registration service through the Dhareeba tax platform on 2 August 2026.
On 30 July 2026, the Portuguese Government published Portaria No. 318/2026/1, approving Model 64 – the Pillar Two Top-up Tax Return – and its accompanying completion instructions. The Ministerial Order entered into force and took effect on 31 July 2026.
Analysis of the domestic implementation of the Pillar Two Global Minimum Tax rules in Monaco for accounting periods beginning on or after December 31, 2026.
Monaco has published draft legislation introducing a Qualified Domestic Minimum Top-up Tax (QDMTT) for multinational enterprise groups. The measure is contained in Bill No. 1129 on the minimum taxation of multinational enterprise groups, dated 14 July 2026 and received by Monaco’s Conseil National on 28 July 2026.
On July 23, 2026, Canada has released a proposed targeted amendment to its Global Minimum Tax Act that would broaden the circumstances in which an intra-group financing or investment arrangement must be neutralised when applying the transitional Country-by-Country Reporting (“CbCR”) safe harbour.
On July 17, 2026, Bill No. 8795 was deposited in the Luxembourg Chamber of Deputies. This would implement the OECD’s January 2026 Side-by-Side package, introduce the permanent Simplified ETR Safe Harbour and extend the Transitional CbCR Safe Harbour.
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