Final answer:
Open market operations refer to the purchases and sales of U.S. government securities by the Federal Reserve to influence interest rates and the money supply.
Step-by-step explanation:
The most commonly used tool of monetary policy in the U.S. is open market operations. Open market operations take place when the central bank sells or buys U.S. Treasury bonds in order to influence the quantity of bank reserves and the level of interest rates. The specific interest rate targeted in open market operations is the federal funds rate. The name is a bit of a misnomer since the federal funds rate is the interest rate charged by commercial banks making overnight loans to other banks. As such, it is a very short term interest rate, but one that reflects credit conditions in financial markets very well.