Hyperinflation: 

While inflation is a sustained increase in the aggregate price level, hyperinflation is very high inflation. Economists generally reserve the term "hyperinflation" to describe episodes when the monthly inflation rate is greater than 50 percent. At a monthly rate of 50 percent, an item that cost $1 on January 1 would cost $130 on January 1 of the following year. Hyperinflation is chiefly a twentieth-century phenomenon. The most widely studied hyperinflation occurred in Germany after World War I. The ratio of the German price index in November 1923 to the price index in August 1922 just fifteen months earlier was 1.02 * 1010. This huge number amounts to a monthly inflation rate of 322 percent. On average, prices quadrupled each month during the sixteen months of hyperinflation. While the German hyperinflation is better known, a much larger hyperinflation occurred in Hungary after World War II. Between August 1945 and July 1946 the general level of prices rose at the astounding rate of more than 19,000 percent per month, or 19 percent per day. Hyperinflations are caused by extremely rapid growth in the supply of "paper" money. They occur when the monetary and fiscal authorities of a nation regularly issue large quantities of money to pay for a large stream of government expenditures. In effect, inflation is a form of taxation in which the government gains at the expense of those who hold money while its value is declining. Hyperinflations transfer wealth from the general public, which holds money, to the government, which issues money. Hyperinflations also cause borrowers to gain at the expense of lenders when loan contracts are signed prior to the worst inflation. Businesses that hold stores of raw materials and commodities gain at the expense of the general public. Hyperinflation reduces an economy's efficiency by driving people away from monetary transactions and toward barter.