Which U.S. act separated commercial banking from investment banking in 1933?

The Glass–Steagall Act separated commercial banking from investment banking in the United States in 1933.

The name commonly refers to provisions of the Banking Act of 1933, sponsored by Senator Carter Glass and Representative Henry B. Steagall. The law was enacted during the banking crisis of the Great Depression and was intended to reduce conflicts of interest and restore confidence in banks.

It restricted commercial banks from underwriting or dealing in many securities and created the Federal Deposit Insurance Corporation. The separation was gradually weakened by later regulatory interpretations and was largely repealed by the Gramm–Leach–Bliley Act of 1999.

The Glass–Steagall Act is often confused with the Securities Act of 1933, which regulated securities offerings. They were separate laws passed in response to the same wider financial crisis.