Say a cardholder carries an average revolving balance of $3,000 at 18% APR and spends $10,000 a year. Interchange is 2%, rewards are 1% cash back, our cost of funds is 5%, expected loss is 3% of the balance, and servicing costs $50 a year. How much does this customer make us annually?

假设一个信用卡客户平均循环余额3000美元、APR 18%，一年刷卡消费10000美元，交换费率2%、返现1%，我们的资金成本5%，预期损失率是余额的3%，每年运营成本50美元，这个客户一年能给我们赚多少钱？