A futures and options exchange that trades contracts in four main areas: interest rates, stock indexes, foreign exchange, and commodities. In 2002, a record 558.4 million contracts with a value of $328.6 trillion traded at the CME, which the CME says is the largest notional value traded that year on any futures exchange. Among the well-known contracts that trade on the CME are futures and options on the S&P 500 index, the Eurodollar, and currency futures. Agricultural products traded include lean hogs, frozen pork bellies, milk, feeder cattle, and live cattle.

The CME was founded as a not-for-profit corporation in 1889 as the Chicago Butter and Egg Board and became the Chicago Mercantile Exchange in 1919. At the time it was founded, the only futures traded were contracts based on butter and eggs. In December 2002, the CME became the first publicly traded U.S. financial exchange when it launched an initial public offering of the Class A shares of its parent company, the Chicago Mercantile Exchange Holdings Inc. The shares trade under the ticker symbol CME. Trading is based on open-outcry pit trading during regular trading hours. The CME also operates GLOBEX, an after-hours electronic trading system.