From January 1st 2025, the new Classification of Economic Activities (NACE Rev.4) will be implemented, introduced by Commission Delegated Regulation (EU) 2023/137 of 10th of October 2022, which updates Regulation (EC) No 1893/2006. This revision is part of the so-called NACE Revision 2.1, which aims to ensure that the classification of economic activities remains a reliable basis for the collection, transmission and publication of statistics at national and European Union levelNACE Revision 2.1 brings significant changes, including the introduction of an additional level of national detail, called a subclass, represented by five-digit codes. In Portugal, all main and secondary activities registered under the Portuguese Classification of Economic Activities Information System (SICAE) will be automatically reclassified to the new CAE Rev.4 codes, replacing the current CAE Rev.3 version.Under legal terms, all companies operating in Portugal are obliged to take part in the Survey for the Reclassification of Economic Activities (CAE Rev.3 – CAE Rev.4), known as IRCAE, developed by the National Statistics Institute (INE), and must confirm or change their economic activity in the new table. This process must be completed by November 30th 2024, based on the obligations set out in article 4 of Law no. 22/2008, of 13th May, and article 4, no. 5 of Decree-Law no. 136/2012, of 2nd July.Answering the survey is confidential and free of charge, and is essential to ensure the correct transition and alignment of economic activities with the new classification. To answer the IRCAE, you must access the IRCAE.INE.PT portal, log in using your tax identification number and password to access the Finance Portal, and fill in the electronic form online, selecting the CAE Ver.4 codes that best suit the activity you carry out.