The central bank has several functions, the most important of which is supervising and monitoring commercial banks. It plays a role in controlling the money supply by influencing the lending and investment operations of commercial banks. The central bank uses several tools to implement its monetary policy, including changes to the required reserve ratio. Commercial banks are required to maintain these reserves with the central bank, as raising this ratio during periods of inflation leads to a reduction in the level of loans and investments by commercial banks, thus causing monetary contraction. Conversely, during economic recessions, the central bank reduces reserves, leading to an increase in the level of loans and investments. Commercial banks, and consequently the availability of cash, and the second of these means is the interest rate imposed by the central bank on commercial bank deposits, whether it is an overnight investment or for a month or more. This rate is an indicator of the interest rates at commercial banks, which should not be lower than the central bank's rate, and the rate also helps The central bank's interest rate controls the money supply in circulation by changing this rate up and down in the medium term. Raising the interest rate means curbing borrowing operations, thus reducing the liquidity ratio in the market, which leads to a reduction in the inflation rate (high prices)