Luxembourg opens Pillar 2 registration and top-up tax declarations

On 6 January 2026, Luxembourg officially opened the Pillar 2 registration process for entities forming part of a Pillar 2 group. Luxembourg constituent entities within the scope of the Pillar 2 rules as from 1 January 2024 and with a calendar year are now required to register for Pillar 2 purposes by 30 June 2026. Registration is performed entity by entity via MyGuichet platform, and key elections, such as the designation of the GloBE Information Return (GIR) filing entity, must be made during this process. Further, the procedures for the GIR filing (if filed in Luxembourg) and declaration of top-up tax (QDMTT, IIR, UTPR) to be paid are now also open.

What is Pillar 2 registration in Luxembourg?

Pillar 2 registration in Luxembourg is the mandatory procedure through which each Luxembourg constituent entity of a Pillar 2 group must register with the Luxembourg Direct Tax Administration via MyGuichet platform), designate relevant filing and paying entities, and enable the filing of the GloBE Information Return (GIR) and any related top-up tax declarations (QDMTT, IIR, UTPR).

• Pillar 2 registration deadlines in Luxembourg - standard deadline: 15 months after the end of the fiscal year in which the group is in scope
• Transitional year deadline: 18 months after the end of the first fiscal year in scope
• For groups with a 31 December financial year‑end first in scope in FY 2024: 30 June 2026

Practical observations for Funds

With respect to Luxembourg funds that are in-scope of the rules, even if a fund may not itself be subject to top-up tax, this does not necessarily exclude that the fund may have to comply with certain legal obligations under the Pillar 2 rules, including the registration for Pillar 2 purposes.

Moreover, based on the current rules, a compartment of an umbrella fund is expected to be treated as a separate ‘entity’ for Pillar 2 purposes. Hence, a separate registration may be required.

For more details on  the assessment of whether a fund falls within the scope of Pillar 2, please see our previous article. 

Information required for Pillar 2 registration in Luxembourg

As part of the registration, the following information must be provided to the Luxembourg Direct Tax Administration for each constituent entity: 

• The identity and tax identification number of the constituent entity;
• The name of the multinational enterprise (MNE) group or large-scale domestic group;
• The identity of the ultimate parent entity (UPE) and the jurisdiction where it is located;
• The fiscal year for which the group falls within the scope of the Pillar 2 rules;
• The fiscal year during which the entity joined the group if that fiscal year is posterior to the fiscal year in which the group came under the scope of the Pillar 2 law;
• The date on which the fiscal year of the group ends;
• The identity of the designated local filing entity (if applicable);
• The identity of the designated group filing entity (if applicable);
• The identity of the designated paying entity (umbrella entity) for the purposes of the Undertaxed Profits Rule (UTPR) tax (if applicable);
• The identity of the designated paying entity (umbrella entity) for the purposes of the Qualified Domestic Minimum Top-up Tax QDMTT (if applicable);
• Name and contact details of the relevant individual with respect to the registration.

Luxembourg joint venture entities as per the Pillar 2 rules and Luxembourg joint venture subsidiaries are also expected to register for Pillar 2 purposes. The information is broadly similar as mentioned above.

What to consider when selecting the designated GIR filing entity?

The registration process allows groups to make certain elections, such as designating a filing entity for the GIR. A designated GIR filing entity is the entity responsible for filing the GloBE Information Return on behalf of the group. When selecting a group filing entity, it is essential to consider whether the chosen jurisdiction has implemented Pillar 2 rules, participates in automatic information exchange (e.g., under DAC 9 or the OECD Multilateral Competent Authority Agreement, MCAA), and provides adequate safeguards for information dissemination.

Luxembourg has aligned with international standards leveraging both DAC 9 and the MCAA for information exchange. In this context, Luxembourg offers a simplified and efficient framework for multinational groups with a local presence to comply with the Pillar 2 group requirements.

Deregistration process and changes to the registration information

In-scope entities that fall outside of the Pillar 2 rules in a subsequent year or cease to be an entity of the group should deregister for Pillar 2 purposes. Similarly, in case information with respect to the registration changes (e.g. migration of an entity or change of filing entity), a notification is to be submitted.

The deregistration must be completed no later than 15 months after the last day of the group fiscal year for which the group is no longer subject to the Pillar 2 rules, or the entity ceases to be part of a Pillar 2 group. The same deadline applies in case of notifications that would amend the registration information.

Observations for dissolved entities

In-scope Luxembourg entities dissolved during fiscal year 2024 are still expected to be registered for Pillar 2 purposes.

Penalties

As per the Luxembourg Pillar 2 Law, a lump-sum fine of EUR 5,000 may be imposed on any Luxembourg constituent entity which fails to register or deregister within the deadline or transmits incomplete or incorrect information in the registration / deregistration forms.

Tax declarations

Luxembourg also published the procedures to file the GloBE Information Return (GIR) and to declare any top-up tax in Luxembourg (QDMTT, IIR, UTPR).

With respect to the GIR, groups have the possibility to file in Luxembourg or in a foreign jurisdiction (subject to exchange of information conditions). The top-up tax declaration is a self-declaration of additional top-up tax to be paid by Luxembourg entities. The top-up tax declaration is expected to be filed by parent entities for IIR purposes, as well as designated umbrella entities for QDMTT and UTPR purposes. In the latter case, if no designation has been made, the top-up tax return could be due by several Luxembourg entities to which top-up tax is to be allocated. If no additional tax is due, the declaration is still expected to be filed (nil filings would be due)*.

* Following the release of an updated FAQ, the Luxembourg tax authorities have since then clarified filing requirements - please see our latest Flashnews for more details.

The first Pillar 2 compliance requirement for Luxembourg entities is opened with deadline on 30 June 2026 for calendar year groups in scope since 1 January 2024.

Groups must carefully consider elections that can be made during the registration process, such as the choice of a designated filing entity or designated paying entity for QDMTT and UTPR.

Failure to comply with registration, deregistration or notification requirements may result in a lump-sum fine of EUR 5,000 per infringement.

For those navigating the complexities of Pillar 2, tailored training and support, such as PwC's Pillar 2 Training Programme, can help ensure your teams are prepared and compliant.

1. Who must register for Pillar 2 in Luxembourg?
All Luxembourg constituent entities and joint ventures that form part of a Pillar 2 group must register, regardless of whether top‑up tax is expected to be payable in Luxembourg. Non-Luxembourg group entities may have registration obligations in their respective countries.  

2. When is the Pillar 2 registration deadline in Luxembourg for FY 2024?
For groups with a calendar fiscal year, the Pillar 2 registration must be completed by 30 June 2026. This deadline reflects the 18-month transitional period applicable to the first year in scope.  

3. How is Pillar 2 registration performed in Luxembourg?
Registration must be completed by entity through the online platform MyGuichet. This procedure requires authentication using a LuxTrust product or an electronic identity card (eID). 

4. Are Luxembourg funds required to register for Pillar 2?
Yes. Luxembourg funds that are in scope of Pillar 2 may still be required to register, even if they are not subject to top-up tax (unless they are stateless entities under Pillar 2).

5. Do Luxembourg constituent entities of a Pillar 2 group need to register in cases where no top‑up tax is expected?
Yes. Luxembourg constituent entities of a Pillar 2 group are required to register even where no top‑up tax liability is expected to arise.

6. Do dissolved Luxembourg entities still need to register for Pillar 2?
Yes. Luxembourg entities of the groups subject to Pillar 2 rules that were dissolved during fiscal year 2024 should be registered for Pillar 2 purposes, and subsequently deregistered.

7. When top-up tax declarations should be filed in Luxembourg?
The filing deadline is 18 months following the end of the relevant fiscal year. For calendar‑year groups for FY 2024, the deadline is 30 June 2026. Top-up-tax declarations must be filed even if no additional tax is due (i.e., nil filings are required).

8. When must the top-up taxes be paid in Luxembourg?
The actual payment of the top-up tax must be done within one month after the deadline to file the top-up tax declaration.

• All Luxembourg constituent entities of a Pillar 2 group must register, even if no top‑up tax is expected
• Registration is completed entity‑by‑entity via MyGuichet
• Deadline: 15 months, extended to 18 months for the first year in scope
• For FY 2024 calendar‑year groups: 30 June 2026
• Failure to register, deregister, or update information may result in a EUR 5,000 penalty per entity