From Wikipedia:

The Federal Deposit Insurance Corporation (FDIC) is a United States government corporation created by the Glass-Steagall Act of 1933. It provides deposit insurance, which guarantees the safety of deposits in member banks, currently up to $250,000 per depositor per bank. The FDIC insures deposits at 8,195 institutions.^[2] The FDIC also examines and supervises certain financial institutions for safety and soundness, performs certain consumer-protection functions, and manages banks in receiverships (failed banks).

Insured institutions are required to place signs at their place of business stating that "deposits are backed by the full faith and credit of the United States Government."^[3] Since the start of FDIC insurance on January 1, 1934, no depositor has lost a single cent of insured funds as a result of a failure.^[4]