Commodities are naturally occurring materials or goods that are collected and processed for use in human activity – such as oil, sugar and wheat. They form the basis of our economy, because the raw materials are needed for the production of food, energy and clothing. Commodities are bought and sold on exchanges, like stocks. Well-known exchanges include the Chicago Mercantile Exchange (CME), New York Mercantile Exchange (NYMEX) and London Metal Exchange (LME).