Endogenous variables are variables that change on their own within the economic system due to the influence of pure economic factors. They are usually not affected by policy factors, such as prices, interest rates, exchange rates and other variables in the market economy. Exogenous variables are variables in the economic mechanism that are affected by external factors, mainly policy factors, rather than by internal factors of the economic system. tax rate. Whether the money supply is endogenous or exogenous involves an important issue, which is whether the central bank can effectively control the supply of money through the implementation of monetary policy, and whether the government can effectively intervene in the economy. In fact, it is difficult to simply say whether money supply is an endogenous variable or an exogenous variable. Money supply is both endogenous and exogenous. The base currency is injected by the central bank, the money multiplier is subject to the macro-control of the central bank, and the money supply is affected by monetary policy to a certain extent. The money supply is exogenous; however, the money supply is also affected by the behavior of other economic entities in the economic system. Economic factors such as investment, income, savings, and consumption make it difficult for the central bank to absolutely control the money supply. Therefore, money supply has both endogenous and exogenous nature.