EN
The article focus on the analysis of the theoretical rationales of state's intervention in economies, which in the theory of a welfare economy are specified as market failures. Generally the theory of micro-economical inefficiencies of the market is not a uniform theory, which means, it is a set of theoretical deliberations of numerous economists, though due to its starting point, which is the structural inability of the market to effectively allocate in Pareto's sense, one might presume that these deliberations are a coherent justification of the state's activity both in the real sphere, as well as in the regulative sphere. The theory of market inefficiencies specified the limits of possibilities of the state's effective actions in economy, and its purpose should be to supplement the market in those areas, in which its effects are different from social expectations.