A floating rate of 30 means a floating rate of 30% on the basis of the benchmark interest rate. For example, the benchmark interest rate of China People's Bank loans for five years and above is 4.9%, so the annual interest rate of loans with a floating rate of 30% is 4.9%× 1.3=6.37%, which is already quite high.

According to the regulations, the bank's loan interest rate can be adjusted up and down on the basis of the benchmark interest rate. Therefore, it is not illegal for banks to raise the loan interest rate by 30% when handling mortgages.

In bank loans, the specific fluctuation range of loan interest rate is not only related to the bank's own floating regulations, but also related to the user's own loan conditions. The better the general user's loan qualification, the lower the loan interest rate will be. If users feel that their loan floating interest rate is too high, they can choose to apply to the bank to lower the interest rate, or reduce their loan interest rate by improving their comprehensive score.