The New Deal reforms, engrafted onto preexisting restrictions in the National Bank Act and state banking laws, largely confined commercial banks to traditional lending activities within a circumscribed geographic area, while protecting them from runs and panics through the provision of federal deposit insurance and Federal Reserve discount window access.
At the same time, investment banks and broker-dealers were essentially prohibited from affiliation with traditional banks. This approach fostered a system that was, for the better part of 40 years, very stable and reasonably profitable, though not particularly innovative in meeting the needs of savers, on the one hand, and of households and businesses wishing to borrow funds, on the other.