In the development process of the economic theory, the focus is shifted from the market, being the only form of coordination of economic activity, to the personal behavior and its impact on economic processes. This reveals the importance of human habits and how they shape the socio-economic behavior. Social relations and interaction become more and more important and are seen as a factor influencing not only the daily decisions, but also the economic behavior of the personality. "Economics is seen by them as an open evolutionary system, experiencing a constant impact by the external environment through culture, political environment, nature, etc."In the development process of the economic theory, the focus is shifted from the market, being the only form of coordination of economic activity, to the personal behavior and its impact on economic processes. This reveals the importance of human habits and how they shape the socio-economic behavior. Social relations and interaction become more and more important and are seen as a factor influencing not only the daily decisions, but also the economic behavior of the personality. "Economics is seen by them as an open evolutionary system, experiencing a constant impact by the external environment through culture, political environment, nature, etc."Neoclassical theory assumes that fully rational, decision-making individuals, through their absolute awareness and using the exchange of goods on the market, strive for equilibrium and actually achieve it. New institutional economy rejects one of the most important postulates of neoclassical theory - the economy's quest for equilibrium, accepting it only as short-term (if at all possible) and uncharacteristic state. The public interest seeks to build more efficient structures/institutions, and by better defining property rights and maximizing the usefulness of each individual, to achieve greater public welfare. The most important concepts of the new institutional economy are the theory of transaction costs, the theory of property rights and the principal-agent problem theory.The problematic area of the present study is the conflicts, arising from the interaction and cooperation between different business partners, united in inter-organizational networks. The subject of this research is the theory and practice of these inter-organizational networks, reflected through the prism of "principal-agent".The expansion of the markets by counterparties and traded goods, as well as by geographic scope, leads to a de-personalization of the exchange, thus an increase in the uncertainty for the participants and consequently the cost of limiting it. The possibility of long-term reiteration of deals with the same contractor is negligible, while at the same time partners become increasingly distanced, virtual and abstract. This stimulates market participants to look for mechanisms to curb the negative effects of expanding markets - commercial contracts, bank guarantees, warranties, betting and trade codes. Their introduction is aimed at reducing the cost of obtaining information about the counterparty, the traded commodities, as well as providing guarantees to prevent opportunistic behavior after the conclusion of the agreement.