The Chicago Mercantile Exchange, now known as the CME group, is the largest derivatives exchange in the world, and one of the oldest.
It has historically served as a major international exchange for commodities futures and options on those futures, along with the Chicago Board of Trade and the New York Mercantile Exchange, which are now part of the CME Group.
The CME Group is now comprised of what used to be several futures exchanges: CME, the CBOT, and the NYMEX. Historically these markets traded in traditional commodities and their futures, and Chicago was the most likely location for such an exchange, being at the hub of the Midwest.
In more recent years, the futures market has become dominated by foreign currency futures. Another change that has taken place over time is that much of the trading used to be done on the floor of the exchanges through open-outcry trading.
In 2015, the CME shut the doors on the “futures pits” and left only two trading floors operational. The vast majority of the derivatives trades on these exchanges today takes place online.