Individuals can make payments by writing checks, which essentially instruct their banks to pay given sums to the checks' recipients.

Time deposits are similar to checking deposits except the owner agrees to leave the sum on deposit for a specified period; while depositors generally can withdraw the funds earlier than the maturity date, they generally must pay a penalty and forfeit some interest to do so. Money also includes money market funds, which are shares in pools of short-term securities, as well as a variety of other assets that can be converted easily into currency on short notice. The amount of money held in different forms can change from time to time, depending on preferences and other factors that may or may not have any importance to the overall economy. Further complicating the Fed's task, changes in the money supply affect the economy only after a lag of uncertain duration.