Subject. This article examines the areas of penetration of FinTech and the impact of the expansion of FinTech and BigTech companies on the structure of the financial sector. Objectives. The article aims to analyze the processes of the emergence of the FinTech phenomenon and its growing penetration into all spheres of finance, identify the consequences of these processes for the structure of the financial sector, as well as formulate the principles for the formation of a balanced structure of the financial sector in the context of its ongoing digitalization. Methods. For the study, I used the systems approach, comparative intermarket analysis, impact analysis of the technological component of economic development at the macro level. Results. The article reveals the main forms and manifestations of the impact of digitalization on the structure of the financial sector and the main activities and types of services of FinTech companies. The article also formulates the principles for the formation of a balanced competitive structure of the financial sector. Relevance. The results of the study can be used by the Bank of Russia and other national financial market regulators to improve approaches to building a modern competitive balanced financial structure.