The changes that have occurred on U.S. financial market over the last several years have led to a dynamic growth of this market. In the past, deposit and credit activities were carried out mainly by banks. Currently, these transactions are conducted by both the banking sector, as well as by several institutions operating in the financial market which, however, do not belong to the traditional banking sector. Due to the fact that non-banking financial institutions were not subject to applicable regulations and a safety net, they have been named shadow banking system. The article describes the system of shadow banking and presents the significance of this system during the financial crisis of 2007-2008. Events that occurred in the financial market have confirmed that shadow banking not only contributed to the occurrence of the crisis but also gave it the character of a systemic crisis. Based on the findings on the causes of the crisis new financial market regulations were introduced in the United States. Although these regulations increase the safety of this market, they still fail to provide its stability.