Which U.S. bank opened the first dedicated credit-card operation in 1958?

Bank of America opened the first large-scale dedicated credit-card operation in 1958.

The bank launched BankAmericard in Fresno, California, on 18 September 1958. It distributed cards to many local residents in an experiment that allowed customers to buy goods on credit at participating merchants.

The launch was costly and produced substantial losses, partly because cards were mailed to people who had not requested them and fraud was difficult to control. Even so, the system established a revolving-credit model that later became a foundation of modern card payments.

BankAmericard expanded beyond California and was eventually licensed internationally. In 1976, participating banks adopted the name Visa. This question concerns the launch of the credit-card operation, not the later rebranding; Visa is the successor brand rather than the original 1958 name.