Today's Commodities include a much broader spectrum then the agricultural products that started it all and play a much larger role in the economy. A commodity is any item that is bought and sold on an exchange. Actually risk is what started the exchange trading of the basic agricultural products. Feedlot operators risk price price of metals, large corporations risk currency exchange rates on international contracts. Large Investment banks and brokerage houses have risk in inventories of bonds.
Mutual funds have large positions in stocks.
With futures trading on the exchanges this risk of future price can be offset to the speculator. The speculator, in effect, pays the farmer, the herder, or mine owner for the right to assume the risk. Why, the speculator endeavors to make a profit. The value of trading in commodities is therefore tied in with the harvesting of crops, the marketing of industrial products, livestock and the related cost of storage. Inherent price risks are the primary reasons for the establishment of the futures contract.