TransferWise has local accounts in the countries they support. Because of that, when a user for example wants his USD converted to GBP, they can accept the payment to their local account in the US with no sending or receiving cost and pay out the GBP from their UK account, again with no sending or receiving cost. To sum it up, there is no actual expensive international money transfer involved, only local transfers that have minimal or no cost and that’s why they can work around the banks’ high.
