There is an overpayment on the credit card. A negative balance on a credit card's outstanding bill means that there was an overpayment on the credit card before the bill date, and the consumption amount in the current period is less than the overpayment, resulting in a negative balance when the balance is not released. This means that there is a balance in the credit card account and no repayment is required in this period. When an overpayment occurs, the user can apply to remit the overpayment to the designated bank account under his or her name, or choose not to receive the overpayment and use it to offset the next period's bill amount.