Luxembourg Opens Pillar Two Registration

On 6 January 2026, the Luxembourg tax authorities (LTA) formally launched the PillarTwo registration tool. Registration is mandatory for all Luxembourg‑based constituent entitiesthat fall within the scope of the Luxembourg minimum effective taxation law of 22 December 2023 (the Pillar 2 Law), as well as entities that qualify as joint ventures or members of a joint venture group in respect of a group in scope of the Pillar 2 Law.

For entities that are in scope of the Pillar Two law as from fiscal year 2024registration must be completed by 30 June 2026 at the latest. The registration form must be submitted electronically.

The LTA has also released procedures for filing the Top-up Tax Information Return (GIR) and declaring anytop-up tax due in Luxembourg, including QDMTT, IIR and UTPR obligations.

1. Background

Under Article 49 of the Pillar 2 Law, each Luxembourg constituent entity of an in-scope group must register with the Bureau Sociétés Diekirchof the LTA no later than 15 months after the last day of the relevant fiscal year (or 18 months after the end of the transition year, i.e., the first year in which the group becomes subject to the GloBE Rules in Luxembourg, or the year in which an entity becomes a member of an in-scope MNE group).

Upon registration, constituent entities should alsonotify the identity and jurisdiction of the entity filing the GIR where no designated local entity exists. A designated local entity means the constituent entity of an MNE group or a large national group that is located in Luxembourg and that has been designated by the other constituent entities of the MNE group or the large national group also located in Luxembourg to file the GIR or to submit notifications on their behalf.

Amendments to the registration are also possible. If a constituent entity ceases to be in-scope, it must be deregistered.

2. Who must register?

Registration is required for:

1. Any Luxembourg constituent entity of an in-scope group.
2. Joint ventures and joint venture subsidiaries within the meaning of Article 36 of the Pillar 2 Law.

A valid Luxembourg Tax Identification Number (TIN) is required. Entities without a TIN must request one from the LTA prior to registration.

3. Information required

A) Fiscal year details

• The first fiscal year in which the groupis in scope (e.g., 01/01/2024 – 31/12/2024)

• The fiscal year in which the entity joined the in-scope group (if posterior to the fiscal year in which the group came in the scope of the Pillar 2 Law)

• The fiscal year for which the registration applies

B) Entity information

• Name

• TIN

• Registration number in the Luxembourg "Trade and Companies Register" (RCS number)

• The name of the MNE group or large-scale domestic group to which the entity belongs

• Confirmation of designated local entity (if applicable)

C) Ultimate Parent Entity

• The identity of the ultimate parent entity (UPE)

• The jurisdiction where the UPE is located

• The TIN of the UPE

D) GIR filing details

• Whether the GIR is filed in Luxembourg.

• The name and TIN of the filing entity (designated, if applicable)

E) QDMTT / UTPR information

• Indication of any designated umbrella constituent entity for UTPR or QDMTT purposes.

F) Contact person

• Name

• Email address

• Telephone

4. Penalties

A fixed fine of EUR 5,000 applies for (i) failure to register, notify changes, or deregister within the required deadlines or (ii) submitting incomplete or incorrect information.

5. How to prepare

A) Before starting registration

1. Confirm Pillar Two scope: determine whether each Luxembourg entity is an in-scope constituent entity under the Pillar 2 Law.
2. Verify TIN availability: ensure each in-scope entity has a valid Luxembourg TIN; request one if missing.
3. Prepare required data.
4. Identify the GIR filing entity: decide whether the GIR will be filed in Luxembourg or abroad, and by which group entity. For this purpose, it is important to consider automatic information exchange agreements in place.
5. Determine whether Luxembourg QDMTT applies for FY 2024and confirm any umbrella entity designations.
6. Establish representation: ensure mandates are in place when an authorised representative files on behalf of the entity.

B) After registration

1. Prepare for GIR filing: start gathering GloBErelevant data consistent with theGIR template.
2. Coordinate globally: ensure Pillar Two compliance is consistent with UPE strategy and other jurisdictions' requirements.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.