The name Fifth Third Bank comes from the merger of two large Cincinnati-based banks, the Fifth National Bank of Cincinnati and the Third National Bank of Cincinnati. In most mergers, only one name survives although U.S. business history is full of companies that adopted some form of joint name.
The entire history of the bank includes its formation as the Bank of the Ohio Valley in 1858. Thus, the bank will celebrate its 150th anniversary in continuous operation in 2008.
The unusual Fifth Third name has been used creatively by the bank, including using 5/3 as a designated, special customer and employee recognition holiday (May 3, known as Fifth Third Day), as well as for the domain name of the bank's website (www.53.com).