Luxembourg Updates Pillar Two FAQs: Broad Registration Requirements and New Compliance Guidance

Luxembourg’s updated Pillar Two FAQs clarify registration, reporting, covered tax treatment, GIR notification obligations, and transitional measures. The key practical impact is that Luxembourg entities within in-scope groups must register broadly with the tax authority, even where no top-up tax is due or a safe harbor applies.

The ACD clarified that tax assessments will be issued to allow taxpayers to pay covered taxes within three years after the relevant fiscal year, provided tax returns are filed on time. These taxes should therefore not be treated as reductions of covered taxes under the Pillar Two rules.

The guidance confirms that every Luxembourg-based constituent entity, joint venture, joint venture affiliate, investment entity, and individual compartment of a multi-compartment structure must register with the tax authority, even where a safe harbor applies or no reporting obligation exists. Stateless entities are excluded, as they are not considered located in Luxembourg. Entities created and dissolved in the same fiscal year must still register and deregister, although a transitional concession allows deregistration within 18 months after the fiscal year-end.

For GloBE Information Return filings, entities exempt from filing locally must notify the ACD of the entity and jurisdiction responsible for filing. Temporary relief applies for Barbados, Switzerland, and Turkey, where Luxembourg will not require local filing until 31 December 2026 if the GIR is filed in those jurisdictions.

The FAQs also clarify that transitional measures apply from the Transition Year onwards. Entities may rely on their own financial statements or the Ultimate Parent Entity’s consolidated accounts, provided data is traceable to the Luxembourg entity. Deferred tax assets and liabilities may be recognised in the financial statements or disclosed only in the notes.

The updated FAQs strengthen Luxembourg’s Pillar Two compliance framework by giving taxpayers clearer rules on registration, reporting, covered taxes, and transitional relief. The most important practical impact is that Luxembourg entities within in-scope groups must register broadly, even where no top-up tax is due or a safe harbour applies.