Money Supply

Money supply, also known as monetary aggregates and money stock, is the quantity of currency and the value of checking accounts owned by the non-bank public. The interest rate is the price of borrowing money. The two are related inversely: as the money supply increases interest rates will fall.
When thinking about the "supply" of money, it is natural to think of the total of banknotes and coins in an economy. That, however, is vastly incomplete. In the United States, coins are minted by the United States Mint, part of the Department of the Treasury, outside of the Federal Reserve. Banknotes are printed by the Bureau of Engraving & Printing on behalf of the Federal Reserve System. The Federal Reserve can also create book-keeping credits in the reserve accounts of its member banks, on the same terms as it can issue paper banknotes (by pledging collateral, usually in the form of US Treasury securities). As it always stands ready to exchange these book-keeping credits for paper banknotes, they are functionally equivalent.
The relationship between the M0 and M1 money supplies is the money multiplier — basically, the ratio of cash and coin in people's wallets and bank vaults and ATMs to Total balances in their financial accounts. The gap and lag between the two (M0 and M1 - M0) occurs because of the system of fractional-reserve banking.
In this respect, all paper banknotes in existence are systematically linked to the expansion of the electronic, credit-based money supply. Coinage can be increased or decreased outside this system by Legal Mandate or Legislative Acts. However, at present the coin base is held in check and used as a complementary system rather than a competitive system with private bank issue of electronic, credit-based money. The common practice is to include printed and minted money supply in the same metric M0.