Money supply

In economics, the money supply or money stock, is the total amount of monetary assets available in an economy at a specific time. There are several ways to define "money", but standard measures usually include currency in circulation and demand deposits (depositors' easily accessed assets on the books of financial institutions).Money supply data are recorded and published, usually by the government or the central bank of the country. Public and private sector analysts have long monitored changes in money supply because of the belief that it affects the price level, inflation, theexchange rate and the business cycle. 

That relation between money and prices is historically associated with the quantity theory of money. There is strong empiricalevidence of a direct relation between money-supply growth and long-term price inflation, at least for rapid increases in the amount of money in the economy.

The nature of this causal chain is the subject of contention. Some heterodox economists argue that the money supply is endogenous (determined by the workings of the economy, not by the central bank) and that the sources of inflation must be found in the distributional structure of the economy.

Source:(www.en.wikipedia.org)