The Roosevelt Institute's Mike Konczal writes about trying to figure out how much a customer is worth to a commercial bank:
"There's whatever you pay in fees. Whatever you having in your checking and savings account is lent out, and the spread is going to be at least 2.5 percent, so they make a ballpark 2.5 percent off whatever you keep in your accounts. And whenever you pay with a credit card or a debit card, your bank is making at least 1.7 percent of the transaction, paid for by the merchant."
For a family with an income of $60,000 per year, he finds, it would work out to $498.12.