Abstract
Aggressive tax optimization (tax avoidance) is one of the main reasons for the erosion of CIT’s tax base. The "anti-optimizing" activities of the lawmaker are focused on two areas: systematic adjustment of internal anti-abusive measures to the standards adequate for highly developed countries and creation of mechanisms allowing tax administration to quickly and effectively identify cases of aggressive tax optimization. As part of this publication, the proportionality of the current MDR provisions is analyzed. This issue is significant as alleged unconstitutionality of MDR regulations is quite often raised in the public debate. Proportionality of MDR is analyzed in the context of reporting and information obligations of CIT taxpayers.