In macroeconomics, money supply refers to the total volume of money held by the public at a particular point in time. There are several ways to define "money", but standard measures usually include currency in circulation and demand deposits. Money supply data is recorded and published, usually by the national statistical agency or the central bank of the country. Empirical money supply measures are usually named M1, M2, M3, etc., according to how wide a definition of money they embrace. The precise definitions vary from country to country, in part depending on national financial institutional traditions.
M0, M1 and M3. US-GDP and M3 of Eurozone for comparison. Logarithmic scale.
New Zealand money supply 1988–2008
Macroeconomics is a branch of economics that deals with the performance, structure, behavior, and decision-making of an economy as a whole. This includes regional, national, and global economies. Macroeconomists study topics such as output/GDP and national income, unemployment, price indices and inflation, consumption, saving, investment, energy, international trade, and international finance.
John Maynard Keynes is considered the initiator of macroeconomics when he published his work The General Theory of Employment, Interest, and Money in 1936