When you say commodity index, CRB is the abbreviation of "Commodity Research Bureau". The varieties of 19 futures contracts covered by the index are as follows:

Agricultural products: soybeans, wheat, corn, cotton, sugar, frozen concentrated orange juice, cocoa, coffee, live cattle and lean pigs.

Energy: crude oil, heating oil, gasoline and natural gas.

Metals: gold, silver, copper, aluminum, nickel.

Among them, the energy category has the largest weight. The research shows that CRB index is a good inflation index, which fluctuates in the same direction as inflation index and bond yield. To some extent, it reflects the trend of economic development.