The keyword is "interchange". (disclosure: I work for Stripe but this is my own recollection of how this all works and could be wrong in the details) There ar

The keyword is "interchange". (disclosure: I work for Stripe but this is my own recollection of how this all works and could be wrong in the details) There are multiple parties at play in a card network transaction: 0. The card holder 1. The card brand (TreeCard) 2. The issuing bank (unknown right now, but this is usually a bank like HSBC, Citi, Wells Fargo, etc) 3. The card network itself (MasterCard) 4. The merchant 5. The merchant's acquirer (Square, for example) 6. The merchant's acquiring bank (whoever Square uses as their baking provider) Each entity other than the card holder and the merchant charge fees. The card holder _sometimes_ is charged a fee, but in this case TreeCard does not. The merchant is always charged a fee (which they can pass onto the customer in certain countries/circumstances). The per-transaction fee the merchant pays is split between the card network and the issuing bank. The issuing bank then generally will share a portion of this revenue with the card brand. Merchants are also charged by their acquiring bank, either on a per-transaction basis or a flat monthly fee.