Luxembourg - Fund taxation: Launch of updated online subscription tax return forms

The Luxembourg indirect tax authorities recently introduced updated online forms for filing subscription tax returns for Undertakings for Collective Investments (UCIs), Specialized Investment Funds (SIFs) and Reserved Alternative Investment Funds (RAIFs) on the MyGuichet.lu platform. Detailed information on the new filing procedures can be found in Circular No. 821.

The updated procedures aim to provide further guidance to the persons submitting the returns (“declarants”) and simplify the management and control of subscription tax returns. 

To facilitate user adaptation to the new procedures, both the existing and new reporting systems for submitting subscription tax returns will operate simultaneously during a two-year transition period, ending in August 2026.

Key changes in the forms

• Additional explanatory notes: These notes assist the declarant when completing the fields of the tax return.

• Automatic currency conversion: Amounts in currencies other than the euro are automatically converted using the exchange rate of the European Central Bank.

• Provisional tax returns: Alternative funds whose official Net Asset Value (NAV) is not yet available on the last day of the quarter now have the possibility to submit a provisional tax return. The declarant is obliged to file a corrective tax return by the deadline for the quarter during which the official NAV becomes available. The corrective tax return will automatically replace the provisional tax return and will be considered final.

• CSSF identification numbers: The format has been modified to allow declaration of the CSSF identification numbers for legal entities and individual compartments, if applicable.

• “Fund of funds” exemption: The new format allows the inclusion of data from both the original fund and the target fund for the "fund of funds" exemption. 

• Summary Page: A new summary page shows the data entered in the form and provides an overview for the declarant.

Additional data requirements

The following additional data is required in the new form:

• CSSF identification number of the legal entity: This applies to UCIs, SIFs and RAIFs
• CSSF identification number of compartments: As needed for the different tax return regimes.
• “Fund of funds” regime: The original fund or sub-fund and the target fund or sub-fund must be identified by their corporate name and their CSSF identification number.
• Identification of the declarant: The party (legal entity) submitting the subscription tax return must be identified by their corporate name and their national identification number (matricule).

Next steps

To ensure a seamless transition and allow users to familiarize themselves with the new form, it is recommended that all declarants test and start using the new tax return form before the transition period ends in August 2026. 

For additional information on this Alert, we encourage you to contact one of our tax professionals.