The instrument of thin capitalization is of key importance in holding companies' international tax planning policies. This measure has been widely adopted by structures conducting cross-border business activity. That notwithstanding, shaping such policies through the use of thin capitalization requires a thorough knowledge of domestic regulations applicable in EU Member States that are concerned not only with the possibilities of employing this measure but also with the provisions limiting the use of thin capitalization. Analyzing the legal provisions on countering thin capitalization, it may be concluded that no measure offers absolute certainty that the negative consequences of the phenomenon of thin capitalization will be countered. The objective of the article is to indicate the most effective mechanisms adopted by international holding companies as well as the tax consequences that they bring about, and tax risk in particular.