The Specifics of the Functioning of Marketplaces in the Context of the Requirements of Competition Law

The article examines the features of digital platforms as multilateral market structures that create conditions for the emergence and strengthening of network effects that influence the formation of market power of transactional marketplace platforms. The basic theories of the functioning of digital platforms are systematized, the features and specific nature of the platform interaction of counterparties on marketplaces are determined, and the features of managing the relationship system under the influence of emerging network effects are described. Sellers are highly dependent on the digital platform due to network effects and the consequences of their influence on the behavior of both consumers and sellers. Network effects are becoming the main source of competitive advantage, but at the same time create high barriers to entry for new entrants. The key characteristics of digital platforms that determine their impact on market participants and the need for specific regulation are highlighted. Typical violations of antimonopoly legislation in the activities of marketplaces in recent years have been analyzed and indicators of market power have been presented. Three main problem areas that fall within the scope of antimonopoly control are identified: unfair market behavior of seller sellers, abuse by the platform against seller sellers and other participants in platform interaction, the influence of external and internal network effects on behavioral decisions and actions of subjects of platform interaction and end consumers. The presented conclusions and suggestions can be used to improve the strategies of companies on marketplaces, as well as to develop regulatory and analytical tools that prevent the risks of antitrust enforcement.