Object - processes of formation and development of tax institutes as norms, mechanisms of support within their implementation and behavioral characteristics manifestations of participants interaction. The purpose - formation of theoretical and methodological positions and systematization of the applied principles of functioning and directions in order to increase the effectiveness of domestic tax institutions with the justification of the determinants of their influence on the expansion or reduction of the fiscal space under conditions of global competition. Methods - theoretical generalization, retrospective analysis, analysis and synthesis, system method, statistical analysis, structural and functional analysis, graphical, abstract and logical, comparison, economic and mathematical analysis. Results - the conceptual foundation of the scientific and theoretical positions of the tax institutions functioning with the reveal of such aspects as interdependence and the interdependence of their impact on the expansion / reduction of the fiscal space that can be used in forming the strategic principles of tax and fiscal policy in the national and local dimension and its implementation. Novelty - firstly: the integrative role of the institutional approach in the study of the nature of the tax is substantiated; it is made by distinguishing of conceptual schemes, categorical apparatus of economic and financial theory in order to reflect adequately the determinants of the tax institutions development; it was generalized the methodological tools of tax study; a retrospective analysis of the tax institutions formation. In the research it was improved: the definition of the institutional essence of taxation, the conceptualization of the essence of the fiscal space, scientific approaches to the rationale for the nature of the conflict of interests between the state and taxpayers, the interpretation of the formal and informal taxation institute, conceptual approaches to the systematization of the functions of tax institutions. In the paper there were made further developments due to scientific approaches to the interpretation of tax system dysfunctions; theoretical approaches, which substantiate the influence of behavioral parameters of subjects of taxation reaction on the course of fiscal processes and the achievement of the production extremums and fiscal functions in the short and long term periods; interpretation, characteristics and chronological boundaries of domestic tax institutions formation, justification of the role of tax elements of the fiscal mechanism in providing of the environmental, economic and social imperatives of sustainable state development. Introduced in the activities of the Committee of Economic Policy on Verkhovna Rada of Ukraine, the Department of Audit of State fiscal service of Ukraine, the Department for Monitoring Revenues and Accounting and Reporting Systems of State fiscal service of Ukraine, the Main Directorate of the State Fiscal Service in Ternopil Oblast, the Regional Center for Institutional Development of the European Region of the World Customs Organization, Shumska united territorial community of Ternopil region, Ternopil National Economic University. Scope of use - Committee on Taxation and Customs Policy of the Verkhovna Rada of Ukraine, Ministry of Economic Development and Trade of Ukraine
