[ForHackernews]

Amex seems to charge between 2.3 and 3.5% [0]. There's no bank in the loop there.

[0] https://www.cardfellow.com/american-express-discount-rate/#P...

[StudentStuff]

Rarely will a business get the 2.3% rate, that is purely a temporary promotion for supermarkets that are new to American Express. Also, Amex acts as the bank, with the same rewards programs and incentives to retain customers.