Modeling the determination of the interest rate and checking its regularity in Iran's usury-free banking

One of the most important challenges of the banking system is the bank interest rate and how it is determined.In many developing countries, without efficient structures, interest rates are usually set by order, regardless of the market situation, taking into account general economic indicators, including inflation, and with a supportive view towards some economic sectors.In Iran, due to some political and economic considerations, the determination of the interest rate was assigned to the Money and Credit Council by order, so that it can provide the basis for growth or strengthening of production or inflation control at its own discretion.  But in reality, this method, firstly, due to being influenced by the directive policies of various governments, and secondly, the failure to achieve some basic goals of the banking system, cannot be a suitable criterion for determining the optimal interest rate.Determining the interest rate of exchange contracts in Iran's usury-free banking system, inspired by Taylor's rule, can help the country's economic policymakers in achieving the goals specified in the country's monetary and banking law and has stabilizing effects on the country's economy. Therefore, in this research, the system of simultaneous equations and the three-stage least squares method (3sls) was used to model the determination of the policy interest rate and obtain the coefficients of the variables.The results of the research for the period 2018-2019 show that firstly, the monetary authorities' reaction to the production gap and expected inflation is not compatible with Taylor's generalized rule and second, choosing the best methods of setting quantitative goals for Iran's economy in development programs will be meaningless until the regular method for determining the interest rate is implemented.