ICBC will reduce the credit limit immediately after credit card overdraft consumption, and release the corresponding credit limit immediately after repayment. For a credit card with a credit limit of 5,000 yuan, if you spend 1000 yuan, the credit limit will be immediately reduced by 1000 yuan, and the available balance is only 4,000 yuan. If 1000 yuan is repaid, the available line will immediately increase by 1000 yuan, making it an available balance of 5,000 yuan.