The need for stable development and effective use of non-banking financial services market tools, as well as the imperfection of the current legislation in this area characterize the unconditional relevance of the topic of this article. The purpose of the article is to determine the purpose of state regulation of non-bank financial services markets, to define the concept of the principles of state regulation of professional financial activity, and to highlight and analyze the main principles of such regulation. It is noted that one of the main elements of state regulation of non-bank financial services markets is the purpose of such regulation. In view of the analyzed scientific positions and legislative provisions, it is concluded that the main goal of state regulation of non-banking financial services markets is: 1) ensuring transparency, reliability and openness in the markets of non-banking financial services; 2) coordination of activities of state authorities on the functioning of non-bank financial services markets; 3) protection of rights, legitimate interests and satisfaction of socio-economic needs of consumers of non-banking financial services; 4) prevention of abuses and violations in the markets of non-banking financial services. It is proposed to define the principles of state regulation of professional financial activity as the main ideas, basic principles, and general provisions of the implementation by the Regulators of a set of measures to regulate, control and supervise the activities of non-banking organizations and other participants in the markets of non-banking financial services in order to create favorable conditions for their functioning. , preventing and countering abuses and violations in the markets of non-banking financial services and ensuring the protection of the legitimate interests of clients. The main principles of state regulation of professional financial activity are highlighted: the principle of legality; principle of commensurability (proportionality); the principle of guaranteeing the rights and legitimate interests of participants in the financial services market (in particular, the rights of consumers); the principle of assessment by the Regulators of transactions, operations, circumstances and events taking into account their economic and factual content; the principle of mandatory licensing of professional financial activity; the principle of exclusivity of professional financial activity.