Commodity money as a theoretical backing for federally issued "gold certificates" to substitute for the gold. Between 1933 and 1970 (when the U.S. officially left the gold standard), one U.S. dollar was technically worth exactly 1/35 of a troy ounce (889 mg) of gold. However, actual trade in gold bullion as a precious metal within the United States was banned after 1933, with the explicit purpose of preventing the "hoarding" of private gold during an economic depression period in which maximal circulation of money was desired by influential economists. This was a fairly typical transition from commodity to representative to fiat money,
Commodity trading in China protect hog breeders from being exposed to sharp price swings. As a major producer and consumer of commodities, China has large potential for developing its futures market. China's commodity futures markets have expanded product ranges and deepened liquidity pools to cater to the increasingly diverse needs of the nation's rapidly growing economy. With increasing volatility in global commodity markets and prices, companies have been expanding their agricultural product, precious/base metal, fuel oil and other commodity-related investments in China. There are three commodity exchanges in China after the merger of 50 exchanges into 14 in 1995 and subsequently into three in