A credit card is a plastic card (or its equivalent) to be used upon presentation by the cardholder to obtain money, goods, or services, possibly under a line of credit established by the card issuer. The cardholder is billed for any outstanding balance. Credit card customers are given a credit limit on the credit card account and can buy goods and services up to this amount. Normally, banks will set different credit lines to the different groups of cardholders. Every time cardholder uses a credit card for purchasing, he/she must sign a sales slip in the presence of the seller, and the signature is then compared to the signature on the card. Copies of the sales slips have the details of the card and they also show the details and amount of the sale. Each month the cardholder receives a statement from the bank which details all the trans- actions in the month, together with the total amount outstanding and any minimum amount that needs to be paid. When the full balance is not settled each month, the cardholder is charged a compound interest ( say 0. 05% ) on the outstanding balance , and this is supposed to provide the bank with a main source of income ( although in China , this revenue is still low because people are reluctant to run into debt) . Other two major sources of credit card services are the annual fee from the cardholders and the percentage of the sales revenue as the commission paid by the seller. A credit card is a plastic card and the like to be used to obtain money, goods, or services and an overdraft is not allowed.