Visa Inc. (), commonly referred to as VISA, is a multinational corporation based in San Francisco, California, USA. The company operates the world's largest retail electronic payment network, managing payments among financial institutions, merchants, consumers, businesses and government entities. Before Visa Inc's IPO in early 2008, it was operated as a cooperative of some 21,000 financial institutions that issued and marketed Visa products including credit and debit cards.

In 2006, according to The Nilson Report, Visa held 44% of the credit card market share and 48% of the debit card market share in the United States."How Visa operates", in Forbes, February 25, 2008

MasterCard Worldwide () is a multinational corporation based in Purchase, New York, USA. Throughout the world, its principal business is to process payments between the banks of merchants and the banks of purchasers that use its "MasterCard" brand debit and credit cards to make purchases. MasterCard Worldwide has been a publicly traded company since 2006. Prior to its initial public offering, MasterCard Worldwide was a membership organization owned by the 25,000+ financial institutions that issue its card.

It was originally created by United California Bank (later First Interstate Bank, subsequently merged into Wells Fargo Bank), Wells Fargo, Crocker National Bank (also subsequently merged into Wells Fargo), and the Bank of California (subsequently merged into the Union Bank of California) as a competitor to the BankAmericard issued by Bank of America. BankAmericard is now the VISA credit card, issued by Visa International.