The Luxembourg Administration of Direct Tax has announced that the deadline for submitting all types of tax returns, including individual income tax returns (M100) and corporate income tax returns (M500), has been moved from the first Monday in February to the first Monday in April.

The change applies to the following forms:

  • M100, Income Tax Return
  • M163, Annual Statement
  • M110, Declaration for the Establishment of Commercial Profit and Commercial Tax Return
  • M500, Entity Declaration (IR, IC, IF)
  • M205, Joint Declaration for the Income of Collective Enterprises and Income Tax Return for Entities
  • M200, Joint Establishment of Income from Collective Enterprises and Co-ownerships
  • M300, Joint Declaration for the Establishment of Commercial Profit and Commercial Tax Return
  • FIS Real Estate Levy
  • M931 RELIBIbis

The first Monday of April 2025, namely 7 April 2025, is the new submission date for all types of tax returns. Instead of the first Monday of February, taxpayers and entities are now invited to submit their returns starting from the first Monday of April. The submission period for individual and entity returns therefore runs from 7 April 2025 to 31 December 2025.

Since employers submit their data during the first months of the year, this new date will allow the Luxembourg Inland Revenue (ACD) services to advance with its project of pre-filling tax returns. In short, the ACD aims to:

  •  Enable the pre-filling of electronic tax returns through data collection from employers, government institutions, and in the future, other actors during the first three months of the year.
  • Improve the quality of collected data and reduce errors through data provided directly by authentic sources.
  • Accelerate the processing of returns, ensuring that returns are processed within shorter deadlines.
  • Offer an improved experience for taxpayers. Taxpayers will only have to verify the information and modify it if necessary.

In 2025, the ACD is also launching the simple declaration project for individuals who only have “salary and pension” income with a minimum flat rate for special expenses, with the aim of gradually extending it to other eligible individuals.