It's going to depend on how the retailer's contract with their merchant account works. Your mom and pop store may just pay a higher rate, and a high txn fee and

It's going to depend on how the retailer's contract with their merchant account works. Your mom and pop store may just pay a higher rate, and a high txn fee and call it a day. Simple contract. For a large retailer like Kroger, there's no way in hell they're leaving all the interchange discounts on the table.