Abstract: This article discusses the international experience in determining the concept of a bank. The authors give special attention to the classification of credit organizations in retrospective and international context, with a particular focus on the division of banks into investment and commercial institutions. The authors describe the existing worldwide trend of banking universalization. The authors analyze the admissibility of banking sector differentiation in connection with the realization of a multi-level banking system in the Russian Federation and the prospects and the influence of formalization of such distinction on law enforcement practice. The methodology of the research consists of general scientific methods of enquiry such as analysis, synthesis, analogy, induction, modelling, as well as the specific methods of legal science including the historical, comparative and prognostication methods. The scientific novelty of the research lies in determining the patterns of banking legal regulation development and the further assessment of a multi-level banking system feasibility. The main conclusion of the research consists in the admissibility of banking business differentiation in Russia, contrary to the prevailing opinion about the necessity of universalization.