On June 20th, 2005, Reuters cooperated with Jefferies Financial Products Company, a subsidiary of Jefferies Group, to adjust the Reuters Commodity Research Bureau (CRB) index and renamed it Reuters/Jefferies Commodity Research Bureau Index (RJ/CRB). The weight of all commodities in the original commodity index is the same, but the new commodity index divides all commodities into four weight grades, with the highest weight of crude oil being 23%, and the lowest weight of orange juice, nickel and wheat being only 1%. The index is adjusted once a month, and the selected commodity price adopts the price of the futures contract in the latest month, instead of the average price of the previous six contract months. CRB index has become the most famous commodity index because it can effectively reflect the overall trend of commodities and provide an effective early warning signal for the changes of macroeconomic prosperity. The New York Futures Exchange (NYBOT) introduced a new commodity futures index contract from July 2005 1 1. At present, the index has been widely concerned and applied in domestic and foreign markets.