The sudden decrease in monthly mortgage payment is usually caused by the following reasons: the user has signed a deposit and loan business with the bank, and when the current deposit account has money, it will be used to deduct the mortgage, so that the amount that the user needs to repay the bank card will be reduced; If the mortgage interest rate is lowered, the monthly supply will also decrease; If there is an error in the banking system and a part of the amount is deducted, the bank will make up the deduction afterwards.

The repayment method of average capital is chosen for mortgage loan, so the loan principal is divided into equal parts, and the same principal and interest generated by the remaining loan are repaid every month. As a result, the monthly supply is naturally less and less.