Luxembourg tribunal rules taxpayer’s informative letter does not qualify as tax claim

On July 9 2025, the Luxembourg Administrative Tribunal (the Tribunal) issued a decision (No. 49156) that distinguishes a modification request under Section 94 of the General Tax Law of 22 May 1931 (the Abgabenordnung, or AO) from a tax claim under Section 228 of the AO. Although subject to appeal, the ruling also provides guidelines on the specific legal requirements that must be met for a tax claim to be considered and processed by the Luxembourg tax authorities (LTA).

The Tribunal determined that a letter from a taxpayer – explaining that its financial statements for the relevant financial year would be amended and that revised tax returns would be submitted subsequently, following the issuance of a provisional tax assessment under Section 100a of the AO – cannot qualify as a tax claim. For the correspondence to qualify as a tax claim, it should, at a minimum, have indicated that the taxpayer considered itself negatively affected by the tax assessment and was seeking a complete reassessment of its taxable basis.

On July 1 2021, a Luxembourg company (the Company) filed its FY 2019 tax returns. On July 14 2021, the tax office issued provisional tax assessments based on Section 100a(1) of the AO. On August 26 2021, the Company submitted a letter (the Letter) to the tax inspector explaining that the financial statements for FY 2019 did not adequately represent its economic reality and did not provide a true and fair view. It further indicated that the financial statements for FY 2019 would be amended and that amended tax returns would be submitted accordingly.

On November 11 2021, the Company filed amended tax returns for FY 2019. However, the LTA treated the Letter as a pure informative letter and the amended tax returns as a modification request. As such, the LTA refused an adjustment under Section 94(1) of the AO as the three-month deadline since the issuance of the tax assessments in July had expired.

On July 12 2023, the Company filed an appeal before the Tribunal to amend or cancel the 2019 tax assessments.

In its ruling, the Tribunal restated that the distinction between a modification request (Section 94, AO) and a tax claim (Section 228, AO) lies in the objective pursued. A modification request aims to correct a specific point of the taxpayer’s taxable basis, while a claim seeks to challenge the taxable basis as a whole and triggers a complete reassessment of the taxpayer’s tax position by the director of the LTA, potentially resulting in a revision ‘in pejus’ (i.e., a less favourable outcome).

In the present case, the Company’s argument concerned only the qualification of its Letter as a tax claim.

According to the Tribunal, for a valid tax claim to be recognised, the taxpayer must explicitly demonstrate that it believes it has been adversely affected by the tax assessment in question and request a formal review of its taxation (see also Cour Administrative, No. 39755C, of January 9 2018). While there is no strict formality required in presenting such a claim, a minimum threshold of diligence must be maintained by the taxpayer in the formulation of the request.

While the absence of formal terminology, such as the explicit use of the term “claim”, does not necessarily invalidate a claim, in the case at hand, the Tribunal found that the Company’s correspondence failed to explicitly challenge the tax assessments, or offer any explanation as to whether it was adversely affected by them. Instead, the communication merely informed the authorities about forthcoming updates to annual accounts without addressing how these updates would affect the tax assessments, thereby failing to meet the requirements for a valid claim.

Additionally, the Tribunal considered that the LTA is not obliged to proactively seek clarification from taxpayers regarding unclear or insufficient submissions and that taxpayers must articulate their claims comprehensively within the prescribed three-month timeframe.

The Tribunal concluded that the Company’s submission did not qualify as a formal tax claim under Section 228 of the AO, as it failed to provide any grievance or request for a formal review of its taxable basis. Consequently, its subsequent appeal was deemed inadmissible.

While the Tribunal’s decision is still subject to appeal, it underscores the importance of taxpayers adhering to procedural requirements when submitting a tax claim. A valid claim must, within the prescribed time limits, explicitly outline the grievances concerning the tax assessment and clearly indicate the taxpayer’s request for a comprehensive review of its assessment. Failure to meet these requirements will likely render the claim inadmissible, as demonstrated in the case at hand.