In general, banks use a+sign to indicate the overdraft of credit card customers. If your balance is+1,, it means that you owe 1 yuan. The bank uses a-sign to indicate the surplus in your book. For example, if you owe 1 yuan, but deposit 2 yuan in your card, your balance is: -1 yuan, indicating that you not only don't owe money, but also have surplus 1 yuan. Note: there is no interest on the excess balance.

Actually, the+sign or-sign is used by a bank to represent its own assets and liabilities, so don't regard it as negative or positive.