Skatturinn sets 21 September 2026 as the filing deadline for the 2026 return for legal entities, covering their 2025 activity. The year in the form's name must therefore not be equated with the financial year whose results are reported.
The administration announces assessment on 30 October. It specifies that a return filed after the deadline may not necessarily be examined before that process. Late filing therefore does not guarantee that the submitted information will be taken into account in the initial tax calculation.
To prepare the filing, the company must therefore allocate accounts and tax information to the correct financial year, then verify that transmission is complete. The assessment date is not a second filing deadline. If documents are submitted late, their processing must still be monitored without assuming they have already changed the announced assessment; this practical difficulty is separate from the simplification offered for annual accounts.
Small entities eligible for Hnappurinn may, after filing their tax return, use a simplified process for annual accounts. This facility follows tax filing: it is neither a replacement tax return nor an extension of the 21 September deadline.