货币市场
A market can be described as a money market if it is composed of highly liquid, short-term assets. Money market funds typically invest in government securities, certificates of deposit, commercial paper of companies, and other highly liquid, low-risk securities. The four most relevant types of money are commodity money, fiat money, fiduciary money (cheques, banknotes), and commercial bank money. Commodity money relies on intrinsically valuable commodities that act as a medium of exchange. Fiat money, on the other hand, gets its value from a government order.