The subject-matter of the article is presentation of the phenomenon of international tax competition which is related to the developing tax policies of countries. It is particularly important to distinguish the phenomenon under discussion from harmful tax competition. In the course of elaboration, it is necessary to mention tax havens that exert a substantial influence both on international and harmful tax competition. Holding companies also influence international tax competition as they adopt numerous tax engineering instruments within the framework of their tax strategies. The present article indicates the most important as well as the most up-to-date ones. The elaboration also presents how the relations and links that are being shaped between countries that are tax havens (though not only) and international holding companies impact international tax competition.

The subject-matter of the elaboration is the mechanism of treaty shopping which is used not only for tax optimization but also tax avoidance. The main beneficiaries of this mechanism are groups of companies running cross-border activity. A special aspect that undergoes analysis in this article are the methods of countering treaty shopping. The issue is directly concerned with the aspects of both domestic tax law and international double taxation agreements. The mechanism of treaty shopping is also connected with the problem of withholding tax. The purpose of the elaboration is to evaluate the effectiveness of the methods of countering treaty shopping in connection with the operation of international holding companies.

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.