Companies are currently working hard to prepare their financial statements for a statutory audit, so this is the right time to revise and update their basic business information. There is a general obligation often neglected by taxpayers because it seems insignificant: the State Revenue Service (SRS) must be duly notified of the taxpayer’s core economic activity according to the statistical classification of economic activities NACE 2.0, deployed uniformly across the EU. In this article we stress the importance of this obligation, remind you of the deadlines, make a few practical recommendations, and describe the proposed migration to NACE 2.1 designed to improve statistical comparability.