A credit card is a high-interest loan, and its interest rate is generally much higher than that of bank loans. According to the information you provided, the monthly repayment amount of the credit card is 40,000 yuan, the monthly interest is more than 800 yuan, and the overdraft limit is 120,000 yuan. Then the interest rate of the credit card is as follows:

Monthly interest rate = per Monthly repayment interest/overdraft limit

= more than 800 yuan / 120,000 yuan

= 0.0067

Annualized interest rate = monthly interest rate * 12

= 0.0067 * 12

= 0.0804

According to calculation, the annualized interest rate of this credit card is about 8.04%. Of course, the actual interest rate may be slightly different because Credit card interest rates sometimes change as market conditions change. Remember not to overdraw your credit too much to prevent interest from doubling.