Therefore, different countries have different types of financial assets and different contents at the monetary level.

Internationally, the classification method of the International Monetary Fund (IMF) is adopted, and the IMF generally divides currencies into three grades:

M0= cash circulating outside the banking system.

M 1=M0+ demand deposits (including private bank demand deposits)

M2=M 1+ savings deposit+time deposit+government bonds.

According to the characteristics of its own financial assets, the People's Bank of China divides the money supply into the following monetary levels:

M0= cash

M 1=M0+ company demand deposit

M2=M 1+ personal savings deposit+unit time deposit.

M2=M2+ commercial paper+negotiable certificates of deposit.

At present, the People's Bank of China has only issued M0, M 1 and M2, and M3 has only been tested.

The basis of currency classification is the degree of currency liquidity.

The classification of money supply level has three meanings: first, it is conducive to the monitoring of macroeconomic operation; Second, it is conducive to the formulation and implementation of monetary policy; Third, it is objectively beneficial to the financial innovation of financial institutions.