The theoretical and methodological principles of researching the tax security of a state were substantiated with the emphasis placed on the two basic economic theories: the social choice theory and the reflectivity theory. The differential features of national tax systems under globalization conditions and their impact on the economic security of the countries that differ in the political regime, the level of economic development, geography and location were identified. There was given the assessment of the cross-sector approach, based on which multifactor effective marginal tax rates in the European Union (EU) are calculated, and of the marginal approach to taxation in general. The analytical study of tax security of the countries of Organization of economic cooperation and development (OECD) was carried out based on the assessment of the specific weight of taxes in gross domestic product, as well as the structure of taxes in the context of taxation objects: income individuals, income corporates, social security contributions, property, value added taxes, other consumption taxes. A particular attention is attached to the problems of taxation of the motion of capital and goods between the EU countries within the framework of ensuring the mutual economic benefits of the collective interests. The assessment of external and internal threats to tax security of Ukraine was performed based on the identification of the shadow economy segment, reasons for its emergence and consequences for the national economy, as well as the dynamics of the absolute and relative indicators of the budget-debt security. The recommendations on strengthening the tax security of Ukraine under the European integration conditions were given.
The aim of the paper is to point out the tax system and activity of tax authorities at carrying out a control activity and as well as the activity of its bodies in order to eliminate tax evasions and tax frauds for a sustainable development of state economy. We pay attention to tax systems and deal with tax frauds. We assume that there is no correlation between the number of registered taxpayers and the total tax collection. We also assume that the majority of findings from the tax controls that were carried out will be on VAT whereas there is no correlation between the findings of VAT controls and the number of tax controls carried out. We refer to the importance to strengthen the battle against tax frauds and tax evasions in Slovakia and the aim is to point out the current tax collection and the overall tax administration in the Slovak Republic with the focus on value added tax (VAT). The final part consists of the proposals for the possibilities to combat against tax frauds and tax evasions more effectively.