yhou wrote:What do you mean they are the issuer and not the processor. If I were to call and apply for a Citi American Express which company would be on the other end answering the phone?
This is really strange. What will come next a Discover Visa card.
Visa, MC, Discover, Amex are all networks. It gets a little confusing because Amex and Discover issue their own cards unlike Visa/MC.
Think of it in computer terms or Mac OS and MS Windows.
Apple makes both the hardware (iMacs, MacBooks) and the software that runs them (Mac OS X). In this case American Express is both the hardware (Platinum/Gold/Green, Blue, SPG, etc.) and software (the Amex network) that allows you to use cards with the Amex logo to make charges.
On the other side you have Visa/MC; think of them like Windows. You can buy many different PCs with Windows installed: Dell, HP, Acer, etc. Just like you can get many different cards with Visa or MC--Citi, Chase, BoA, etc. In this case, Visa/MC is the network (Windows) and Citi, Chase, etc. is the hardware (Dell, HP, etc.)
Visa/MC used to tell banks they could not issue Amex cards if they issued Visa/MC. The SCOTUS ended that about 10 years ago and since we have seen banks traditionally associated with Visa/MC start to issue Amex cards—although the number is still relatively small compared to the American Express Company.
Much of this applies to Discover as well but I left them out for simplicity.