The paper is relevant because investment activities with the participation of banks, due to their special legal status, have a number of features of legal regulation that take into account the need to realize public interest in the activities of banks and their significant role in the economy. The basis for the emergence of discussions on the separation of investment and banking activities at the legislative level was the adoption of the American Glass-Steagall Act, containing the concepts of a segmented model of investment and classical lending. The paper analyzes the directions and legal forms of investment activity of banks in Russia, the difference between investment activity of banks and the classical understanding of banking activity. The main criterion for differentiation is the goal of investment and credit activity, the quality of risk, the mechanism for generating income. Investment activity, unlike credit, has a wider range of funding sources. The demarcation criterion is also the responsibility of the bank, which it bears when entering into relations with individuals in the framework of investment and banking activities. The features of the legislative regulation of banking activities in the securities market are identified, the role of banks in project financing and alternative (Islamic) financing is determined. It is proved that the investment activity of banks is a much narrower concept than the concept of a bank in the investment market, including the securities market.