The main product of AMEX is access to its cardholders. Because they are picky about who receives their card, an amex cardholder is likely to spend more than a

The main product of AMEX is access to its cardholders. Because they are picky about who receives their card, an amex cardholder is likely to spend more than a cardholder of another network. This is why businesses accept amex despite the much higher merchant fees; the higher spending by the cardholders means that businesses accepting amex tend to come out ahead anyway, by virtue of selling more to amex cardholders.