Luxembourg clarifies Pillar Two registration, notification, and filing obligations

At a glance

Luxembourg's updated Pillar Two FAQ clarifies registration and filing duties.
 

A closer look

On 5 and 18 June 2026, the Luxembourg tax authorities published updates to their FAQ on the Pillar Two law. These updates provide further practical guidance on key administrative and compliance aspects, relevant for groups with Luxembourg entities. They address registration requirements, notification obligations, and the circumstances in which Luxembourg top-up tax returns may need to be filed.

Registration requirements
The FAQ confirms that a broad range of in-scope Luxembourg entities may be required to register under Pillar Two. This can apply even where no return is ultimately due. Groups should verify the registration status of their Luxembourg entities and confirm the related compliance obligations.
 

Notification for centralized filing
The FAQ also clarifies the notification process where a Luxembourg entity relies on the exemption from filing the Global Anti-Base Erosion (GloBE) information return locally. It explains how the identity and jurisdiction of the filing entity should be notified as part of the registration process. This is a key practical requirement for groups intending to rely on centralized filing.

Top-up tax return obligations
The FAQ provides guidance on Luxembourg top-up tax return obligations under the Income Inclusion Rule (IIR), the Undertaxed Profits Rule (UTPR), and the Qualified Domestic Minimum Top-up Tax (QDMTT). It highlights that, in many cases, no Luxembourg top-up tax return may be required. However, this still needs to be assessed carefully, based on the group's facts and the position of the Luxembourg entities concerned.