In this chapter, we reviewed money markets, which are markets that trade debt securities with original maturities of one year or less. The need for money markets arises because cash receipts do not always coincide with cash expenditures for individuals, corporations, and government units. Because holding cash involves an opportunity cost, holders of excess cash invest these funds in money market securities. We looked at the various money market securities available to short-term investors and the major borrowers and issuers of each. We also outlined the processes by which each of these securities are issued and traded in secondary markets. We concluded the chapter by examining international issues involving money markets, taking a particular look at euro money markets.