The publication “Structural changes of groups of the national economy entities in the REGON register, 2021” presents data on number and structure of the national economy entities entered in the National Official Business Register (REGON) at the end of 2021 against the respective data as at the end of 2020. The data concerns entities of the national economy entered in the REGON register and includes legal persons, organizational entities without legal personality, natural persons conducting economic activity, classified into individual sections and divisions of PKD 2007, voivodships and subregions.