Theoretical provisions for substantiating the essence of the concept of «tax system»

The article considers the peculiarities of the tax system functioning as a component of the financial system of the state. Its role in macroeconomic regulation and behaviour of its participants is determined, especially in the period of financial instability and economic cyclicality. The scope of domestic scientific views and approaches to the interpretation of the essence of the concept of ‘tax system’ is studied. Based on the analysis, the interdependence of fiscal, regulatory functions and basic principles of the tax system is highlighted. Attention is focused on the study of the tax system through the prism of tax and budget law with the argumentation of classification into its external and internal environment. The author distinguishes the conceptual components of the tax system as a complex of taxes and fees, including the regulatory plane (not only tax law), the organisational (institutional system) and the component of the taxpayer complex (headed by its psychological component). The author states a set of factors of economic (unemployment, inflation, efficiency of the budget system), social (demographic situation, migration), political and other influence on its development (resource, scientific and technological progress, globalisation, integration, etc.). The basic models of the tax system (Anglo-Saxon, Eurocontinental, Latin American and mixed models) are stated. The author substantiates a universal set of problematic issues of the functioning of the tax system of each country of the world (issues of digitalisation, optimisation and flexibility of approaches to taxation of small and medium-sized businesses, minimisation of tax evasion and shadowing of tax relations) and key development trends. The study states the principles of functioning of the tax system with the participation of psychological influences that determine the system of tax relations, expectations and responsibilities.