Modern tax systems are characterized with the need for an economically justified and legally correct determination of the tax consequences of operations carried out in the context of the use of complex ambiguous models of contractual relations (business models). Taxation when using such models, as a rule, is accompanied by the need to conduct an analysis aimed at clarifying the essential economically justified reason of either the business model as a whole, or individual elements of the operations carried out, for example, the essence of certain payments made by the taxpayer or in his favor. The results of the preliminary analysis showed that one of the most relevant areas of research in this area is a set of issues related to the methodology for determining the customs value of goods as a basis for calculating customs duties. In some countries, it is one of the components of the tax base for value added tax and excise taxes paid as part of customs payments. At the same time, the study of both Russian and international experience shows the special significance of the scientific development of two directions in this area, namely: formation of methodological approaches to the concept of an actual buyer of goods, the customs value of which is determined; qualification based on the actual economically justified reason of individual payments, including those that are not formally included in the customs value of goods based on the principles formulated by the World Trade Organization. As part of the scientific development of the above questions, the results of which are presented in the article, the following research methods were used: analytical, graphic, generalization and economic modeling.