2026 annual-return corrections due by March and April 2027

Filers that submitted an erroneous vuosi-ilmoitus annual information return correct it as soon as possible, so the data still reach individual customers' pre-completed tax returns. Corrections to data reported to the tulorekisteri income register are made in the tulorekisteri, not under this procedure.Vero

This correction procedure does not cover nominee-registered shares with dividends paid to persons with limited tax liability, FATCA, CRS and DAC2 annual returns for financial institutions, the reporting platform operator's annual return (DAC7, VSDPIFIN), or crypto-asset annual returns (CARF/DAC8 and FICARF).Vero

For 2026 annual returns, electronic corrections are due by 1 March 2027 for the data to reach the pre-completed returnsVero, and by 26 April 2027 for the correct data to reach the individual customers' tax decisions even when they miss the pre-completed returnVero. Data corrected after 26 April 2027 are still taken into account in taxation, and the individual customer's taxation is corrected or the tax decision adjusted where necessary. The previous round showed 6 March 2026 and 24 April 2026 for 2025 returns.

Annual returns are corrected with a replacement return. A replacement is filed only for those recipients or other taxpayers whose original data were incomplete or erroneous.Vero The new specification replaces the earlier specification's data: the new specification states all of the recipient's data, both corrected and data that were correct in the original return, and the replacement states the taxpayer's whole calendar-year data.

Because a new return always replaces the previous one, a taxpayer can have only one return under the same identifiersVero. Identifiers include the payer identifier (personal or Business ID), the tax year, the recipient or other taxpayer identifier (personal or Business ID) and the payment type. Where identifiers are corrected, the erroneous return is first deleted in full and then a new return with the correct identifiers is filed. The identifiers for each annual return appear in its completion instructions and record description.

The outer time limit for correcting data given on annual returns is the same as for income-tax appeals, set out in guidance Oikaisuvaatimus tuloverotuksessaVero, which allows an appeal within three years from the start of the year following the tax yearVero and gives the filing tracks in OmaVero and on paper or free-form application.

Corrections to annual returns filed in OmaVero are made in OmaVero, including returns originally filed in OmaVero, the Verohallinto e-service or Lomake.fi. Use of Lomake.fi ended in full on 29 February 2024, and returns filed there are corrected in OmaVero; the OmaVero correction instructions are year-specific. Changes to file-filed annual returns have been made to the record descriptions, and filers confirm with their software vendor that the software reflects the record descriptions in force. Further help is available in guidance Vuosi-ilmoitusten korjaaminen ja poistaminen OmaVerossa, in the record descriptions, and from Verohallinto service number 029 497 038 for annual returns on dividends and other payments.

Where the accounting firm changes mid-year, the payer ensures that the first-half data from the previous firm reach the new firm, the two halves are added together before the annual return is sent, and only one return for the whole year is given, otherwise only second-half data reach personal taxation. Where software changes mid-year the same adding applies, and files from two different programs may be given separately only with different software identifiers, otherwise two returns for one recipient with different software data both stay active rather than replacing each other.

The rules are stated in Verohallinto guidance Vuosi-ilmoitusten korjaaminen, with appeal periods in Oikaisuvaatimus tuloverotuksessa and OmaVero correction practice in Vuosi-ilmoitusten korjaaminen OmaVerossa.