This article deals with the characteristics of the institutionalization process of the financial sector in Ukraine and the role of the corporate securities market in it. It is determined that the modern domestic financial sector is characterized by significant institutional imbalances, primarily due to the insufficient effectiveness of state policy in this area. For many years, banks have been the key players in the domestic financial sector, which significantly reduced the level of financial inclusion. The development of non-banking financial institutions has been fragmentary, significantly undermining public trust in the financial sector. In particular, this concerns the activities of credit unions in Ukraine, where the market volumes of private pension provision have been minimal for a long time. Some existing institutional imbalances were overcome through the rapid digitalization of certain segments of the financial market, but the overall level of financial inclusion remains low. The process of institutionalization of the domestic financial market occurred against the background of the weakness of the corporate securities market. The article notes that this situation was a consequence of the lack of interest from joint-stock companies in market methods of capital attraction. Along with this, domestic financial institutions are not interested in investing in corporate securities. Thus, the reluctance of public corporations to place their securities on the market coincides with a peculiar investment strategy of financial institutions. As a result, the volumes of the primary corporate securities market in Ukraine are minimal (especially in the stock market), and government securities dominate the secondary market for a long time. This situation poses a series of threats to Ukraine's economic development and requires appropriate actions from the state aimed at the activation of the corporate securities market. It can now be stated that domestic public corporations are non-competitive in the global financial space, which destructively affects their market positions.