The Current Account Switch Service (CASS)

[jwhiterz (Jack)]

This should answer your question

Monzo Staff Weekly Q&A - Annual Report Edition!

For the merchant spend, yep there is a thing called ‘Point of Sale Interchange’ that Mastercard and Visa offer, and is regulated in the EU. I think of it like a commission we get when customers use our card to make purchases, so all banks get this. On the other things you’ve listed, we don’t make money on those, but we do incur costs whenever they happen

We’re talking pennies per time though I believe.