The bank recalculated the monthly repayment amount according to your loan balance, so the principal repayment in January increased, in addition to the interest is paid in stages, before December 31, 2012 in accordance with the previous interest rate accounting, and after that in accordance with the adjusted interest rate calculation. So generally the first month of the following year after the interest rate is adjusted, if the interest rate goes down, the amount payable will go up, and if the interest rate goes up, the amount payable will go down.

For non-fixed rate personal housing loans (including commercial and provident fund) with a loan tenure of more than one year, the new interest rate will be applied to the corresponding interest rate bracket from January 1 of the following year in case of statutory interest rate adjustment during the loan period.

After the interest rate adjustment, loans in January will bear interest in segments, i.e., loans before January 1 will bear interest at the pre-adjustment interest rate, and loans thereafter will bear interest at the new adjusted interest rate, while loans in February and subsequent months of the same year will bear interest at the new interest rate of the loan.

The interest rate is the ratio of the amount of interest due for each period on the amount borrowed, deposited or lent (called the total principal amount) to the par value. The total interest on the amount lent or borrowed depends on the total principal amount, the interest rate, the frequency of compounding, and the length of time for which it is lent, deposited, or borrowed. The interest rate is the price the borrower pays for the money he borrows and the return the lender gets for delaying his spending and lending to the borrower. The interest rate is usually calculated as a percentage of the principal over a one-year period.

In general, interest rates are expressed in terms of annual, monthly, and daily rates, depending on the standard of the term of measurement.

In the modern economy, the interest rate as the price of money, not only by the economy and society in the constraints of many factors, and, changes in the interest rate of the whole economy to produce a significant impact,

Therefore, modern economists in the study of interest rate decision, pay special attention to the relationship between the various variables as well as the whole economy of the equilibrium problem, the theory of interest rate decision has also experienced the classical interest rate theory, Keynesian interest rate theory, loanable funds interest rate theory, IS-LM interest rate analysis and contemporary dynamic interest rate model evolution, development process.

Keynes believed that savings and investment are two interdependent variables, not two independent variables.

In his theory, the money supply is controlled by the central bank and is an exogenous variable with no interest rate elasticity. The demand for money then depends on people's psychological "liquidity preference".

The theory of the interest rate on loanable funds is a neoclassical theory of interest rates, which was proposed to modify Keynes's "liquidity preference" theory of interest rates. In a way, the loanable funds interest rate theory can actually be seen as a synthesis of classical interest rate theory and Keynesian theory.

The famous British economist Hicks and others think that the above theory does not take into account the factor of income, and therefore can not determine the level of interest rates, so in 1937 proposed a general equilibrium theory based on the IS-LM model. Thus, a theory of simultaneous determination of interest rates and income under the interaction of four factors, namely, savings and investment, money supply and money demand, was established.