Money is legal tender issued by a government, including paper currency and coin. Other negotiable instruments and cash on deposit in banks are also considered to be money. The supply of money in the economic system of a country is monitored very carefully and measured on a regular basis by governmental authorities. The most common measures of money supply are M1, M2, and M3. Most economists would agree that economic growth and inflationary trends of a country are determined by money supply. Money supply in the United States is managed mainly by the Federal Reserve Board through its bank reserve requirements, the discount rate it charges to banks for money, as well as its open market operations conducted through the issuance of securities.