Introduction

Currently, 87 countries – representing more than 90% of global GDP – are considering central bank digital currency (CBDC). It is therefore crucial that central banks understand the implications of CBDCs for financial stability and monetary policy. CBDCs should not harm the country's economy. In particular, they should not become a source of financial disruption that could disrupt the transmission of monetary policy. Recently, the details of the Central Bank's digital currency, which is called "Digital Rial" in Iran, have been published by the Central Bank of Iran. This study seeks to examine the changes in the country's monetary policies with the introduction of the Digital Rial by the Central Bank using the system dynamics method. The results of this study show that with the issue of the Digital Rial, the increasing coefficient of money decreases and reduces the money supply, and because the Digital Rial has the same nature as banknotes and coins, it can reduce the power of banks in creating liquidity. As a result, the central bank can use Digital Rial as contractionary monetary policy tool to control inflation in the country.

Methodology:

In order to provide a working solution for the research problem and to understand the importance of the topic, this study tries to use the system dynamics method to present a dynamic model of the relationship between digital currencies and its effect on monetary policies in Iran's economy. System dynamics is a method for modeling systems using accumulation, state and flow variables, which was developed in the 1960s by Professor Jay Forrester at MIT University. This model became very famous in the 70s thanks to the publication of the book "Limits to Growth". This book used the system dynamics model to analyze the absurdity of the idea of unlimited growth. Today, the most comprehensive source for the system dynamics model is the book "Business Dynamics" by Professor John Sterman (2000, MIT University). System dynamics can model the technical and social aspects of complex systems created by the adoption of Bitcoin and other cryptocurrencies. The idea of interaction between factors related to human behavior and the (technical) framework of the system is a perfect way to study the economic dynamics of this new form of money.

Results and Discussion:

The results showed that with the issue of Digital Rial, the increasing coefficient of money decreases and money supply decreases, and because the Digital Rial has the same nature as banknotes and coins, it can reduce the power of banks to create liquidity. On the other hand, the estimates of this research showed that the effect of the ratio of banknotes and coins on the increasing coefficient was not significant, and also the increasing coefficient had less effect on the money supply in pre-2013 period, which can be attributed to the effect of the increasing effect of the money supply. Most of the banks know that in increasing the country's liquidity, the use and expansion of the Digital Rial as a contractionary monetary policy tool will be effective in the current economic conditions. Also, this effect can be more effective with the increase in the use of electronic payments and new banking methods, because in addition to facilitating exchanges and reducing money printing costs, the use of Digital Rials also has the advantages of current electronic payments, with the difference that this part of deposits is not under the control of banks and is kept in electronic wallets, so they will not have the power to create liquidity. Therefore, the effectiveness of this money depends on the choice of the central bank to deposit electronic wallets in commercial banks, as well as the volume of this money issue.

Conclusion:

Considering the effect of Digital Rial on monetary contraction, it is suggested to design effective incentives in the design of Digital Rial, because the expansion of the use of this currency can be effective in controlling inflation. Among these incentives, we can mention fixed fees and lower taxes in transactions compared to other means of payments or increasing the limit of convertible money. Also, the requirement to purchase certain goods only through Digital Rial and to designate special shopping centers that only pay with Digital Rial (similar to China's policies on the use of Chinese Yuan by people) can also be other incentives to use Digital Rial. Also, due to the facilitation and acceleration of exchanges, the expansion of the Digital Rial can be effective in controlling the money supply besides the advantages of electronic payment methods.