Pork bellies are the underside of the hog, from which bacon is made. Pork bellies and pork belly futures contracts have been traded on the Chicago Mercantile Exchange since 1961. Pork bellies can be kept in cold storage for an extended period of time, and generally it is the frozen bellies that are most actively traded. Bellies typically weigh around 13 pounds. Prices vary depending on the amount of inventory in cold storage and the seasonal demand for bacon.

Pork Bellies were referenced in the film Trading Places, which featured futures trading.

Spectrum Commodities pork bellies primer

Pork | Commodities market