Problems and obstacles concerning national banking system; With an approach to a mechanism for determination of the actual interest rate and its solution

Undoubtedly، banks are authorized to use the deposit investments in exchange or participation based contracts. From the jurisprudential – legal point of view these contracts relate to exchange and participation based contracts rather than the mechanism for the determination of interest rate. For instance، the sale on installment outlines the framework of the contract and nor the mechanism of the determination of this contract''s interest rate. The contract interest rate may be determined independently from the interest rate or usury rate determined in the actual economy، as it may be possible to derive the interest rate of this contract from the usury rate or interest rate in real economy. If the interest rate of this kind of contract is derived from the usury rate، no lawyer or jurist cannot criticize the installment buying and selling which its rate is derived from the interest rate and invalidate the transaction as well as economists cannot accept that such an interest rate is moving away from the actual interest rate. In fact، the economic problems should not be offered to jurisprudence to find jurisprudential solutions، but، there exists economic solutions to economic problems. Here، finding an underlying mechanism for determination of interest rate in all the exchange and participation based contracts is identified as an economic problem. That some economists have presented the solutions for these economic problems was discussed in this paper.