Visa and Mastercard set interchange rates, which can average between 2-4 per cent of the transaction amount. But they only get a small slice of this. In a $100 purchase, for example, a shop might pay 2.5 per cent — or $2.50 — in fees to accept a credit card payment. Of this, Visa or Mastercard, which operate the networks that connect cardholders with banks and merchants, collect perhaps 20 cents. The lion’s share of that fee — about $1.80 — goes to the bank that issued the credit card that is being used. Another 50 cents is collected by the merchant acquirer, or companies such as Block or Stripe that provide the shop’s point-of-sale service system.

https://www.ft.com/content/0208fbcc-804f-427a-9545-8a26fb08052e