Of course, commercial banks may provide additional services. Congress felt that investment banking was too risky for commercial banks. One provision of the Glass-Steagall Act was to prohibit commercial banks from underwriting securities and from investing in common stock for the banks' own portfolio. The Glass-Steagall Act does provide some exceptions for underwriting securities. Commercial banks may underwrite debt.
Many large banks are dealers and market makers for government obligations.
Over the last few years the Fed has reviewed the request of certain well-capitalized banks and accordingly, now allows a few banks to underwrite equity securities. State chartered banks may join the FDIC deposit insurance. Promotes safe banking standards. Audits banks to ensure compliance with its standards. Prevents troubled banks from failing.