The Chicago Mercantile Exchange (CME Group) is a publicly-traded derivatives-based exchange (NasdaqGS: CME), and is currently the largest futures exchange in the world in terms of number of contracts outstanding (or open interest).
The Chicago Board of Trade (CBOT) is a publicly-traded exchange (NYSE: BOT) that specializes in futures and options trading. It is highly active in markets such as agriculture, energy, equities, and US Treasuries, providing an important risk-management function for thousands of its CBOT members.