thumb|right| Money supply decreased significantly between Black Tuesday and the Bank Holiday in March 1933 when there were massive bank runs Monetarists believe that the Great Depression started as an ordinary recession, but that significant policy mistakes by monetary authorities (especially the Federal Reserve) caused a shrinking of the money supply, which greatly exacerbated the economic situation, causing a recession to descend into the Great Depression.
thumb|right| Money supply decreased signific,antly between Black Tuesday and the Bank Holiday in March 1933 when there were massive bank runs Monetarists believe that the Great Depression started as an ordinary recession but that significant policy mistakes by monetary authorities (especially the Federal Reserve) caused a shrinking of the money supply, which greatly exacerbated the economic situation, causing a recession to descend into the Great Depression.