Deflation occurs when supply exceeds demand. World War I, when the began and 1917 when the U.S entered the war, U.S gold reserves rose 64%, as Europe exchanged its gold for U.S goods. Once the war end, gold continue to flow into the U.S as allies repaid their war debt. The credit base double during this time period, industrial machinery and equipment output rose by 205% and all producer durables increased by 257%. This surge in industrial capacity created an oversupply by 1926 and as a result the wholesale price declined. In 1921 the fed sold large amounts of government debt and caused credit to contract by 8% through the economy into a brief recession. When the dollar earnings of the surplus nations are deposited into their domestic banking systems, those dollars, being exogenous to those banking system, act as high powered money and spark off an explosion of credit creation. Excessive credit creation permits over-investment, which, in turn, causes excess capacity and deflation. So long as the huge US current account deficits continue to flood the world with dollars, global deflationary pressures are very likely to continue to build, as reckless credit creation results in more industrial capacity than can be absorbed at the prevailing price level.

What forces in 2009 are causing Price to drop?