Euro Tax Flash from KPMG's EU Tax Centre

On April 30, 2026, the OECD released the GMT Implementation Toolkit (the “Toolkit”) and the GMT Frequently Asked Questions (“FAQ”).

The Toolkit is primarily aimed at tax administrations implementing GMT but may help businesses in two ways:

• illustrating the variation and divergence in local rule interpretation and application of the GMT, a key focus area ahead of the June 2026 filing deadlines;
• calling for grace periods for return correction, penalty relief and return-filing extensions where merited; though it remains to be seen whether administrations follow through on this.

The FAQ document is a refresh of an earlier FAQ document and includes 27 questions divided across five sections. Two sections deal with the basic GMT charging and calculation rules (and largely replicate the content from the earlier FAQ document), with the remaining three sections dealing with the Side-by-Side Package. 

On April 30, 2026, the OECD released the GMT Implementation Toolkit (the “Toolkit”) and the GMT Frequently Asked Questions (“FAQ”). It is the first update since the publication of the Side-by-Side Package in January 2026. For more information on the SbS Package, please refer to E-News Issue 224.

The Implementation Toolkit is a practical guide developed through the  the Amsterdam Dialogue involving the OECD-led Forum on Tax Administration (FTA) and other stakeholders, including business representatives. Its primary objective is to assist tax administrations with the implementation, administration, and enforcement of the GMT rules.

While primarily aimed at governments, the Toolkit also provides useful insights for businesses as they prepare for filing and compliance, including:

• Legal implementation approaches: Discussion of approaches jurisdictions use to incorporate the GloBE Model Rules and OECD Commentary into domestic law. The Toolkit illustrates how differences in legislative techniques (e.g., cross‑references to OECD materials or incorporation of new OECD guidance into domestic law) as well as local guidance on certain GMT rules (e.g., in the form of general rulings, explanatory notes, circulars, FAQs, etc.) can result in divergence and staggered implementation timelines across countries.
• Compliance best practice guidelines: The toolkit provides best practice guidance on compliance mechanics, covering registration requirements (encouraging minimization where possible), filing the GloBE Information Return (GIR), and local GMT returns, payment mechanisms (discouraging advance or instalment payments), and penalty regimes encouraging grace periods for correcting errors and extensions of filing deadlines where appropriate).

For more information, please refer to a detailed report by KPMG International.

The April 2026 FAQ document is an update of an earlier FAQ document and includes 27 questions divided across five sections. Two sections deal with the basic GMT charging and calculation rules (and largely replicate the content from the earlier FAQ document), with the remaining three sections dealing with the Side-by-Side Package.

While most of the FAQs summarize how the rules should operate, the FAQs help to illustrate how certain aspects of the Side-by-Side Package are intended to apply in practice, including clarifications on whether income-based tax incentives can be Qualified Tax Incentive (“QTI”) in the context of the Substance-based Tax Incentive Safe Harbour.

For more information, please refer to a detailed report by KPMG International.

The Toolkit notes that the Amsterdam Dialogue will continue to develop a coordinated risk assessment framework and dispute prevention and resolution tools, though it does not specify when this may be published.

Over the remaining weeks before GIR filing due from June 2026, MNEs may want to closely monitor last-minute compliance rule clarifications from national tax administrations, and potentially coordinated OECD guidance on this issue. Further Administrative Guidance is expected in the coming months, including on the SBIE treatment of mobile assets, hyperinflation adjustments, or the treatment of real estate investment vehicles.

Should you have any queries, please do not hesitate to contact KPMG’s EU Tax Centre, or, as appropriate, your local KPMG tax advisor.