Competition in antitrust legislation is considered in its narrow sense — through the influence of business entities on the conditions of circulation of goods, which presupposes that they have a certain degree of market power. The concept of «competition» must be considered broadly through the use of objective characteristics that determine its levels and intensity, taking into account the various market factors that have the greatest impact on competition and its prospects. It is not enough to establish the formal conformity of the assessed actions with the envisaged prohibitions - it is necessary to establish that when committing actions the economic entity took advantage of its dominant position and its market power in order to limit competition. Market power is, in a legal sense, a property of state as a form of legal fact, and its implementation is carried out mainly through a contract as a legal means of regulating relations. The principle of freedom of contract does not apply in conditions of disparity of negotiating capabilities and unfair, excessive use of negotiating power. But market power can also manifest itself on the buyer’s side. Commodity markets may not be equilibrium, affected by many factors that are not always related precisely to the behavior of the dominant. Regulatory approaches enshrined in antitrust laws require revision, changes in the methodology for analyzing the state of competition, and restrictions on the capabilities of entities that unnecessarily use bargaining power.