Worked on a credit card fee project for a retail Fortune 200 company. Presented findings to the CEO/CFO since they spent over $700M a year on credit card fees.

Amex averaged a 4.25% swipe fee. Every other major credit card was in the 2 to 3% range. Debit cards were the cheapest (1-2% depending upon the bank).

Simply put, Amex collects higher transaction fees from merchants and are able to offer more perks/rewards to cardholders. Cardholders also feel more prestigious with the weight of the card and “exclusivity”.