CME Group Inc. (formerly Chicago Mercantile Exchange Holdings Inc.) is an American financial services company based in Chicago, Illinois. It operates financial derivatives exchanges, including the Chicago Mercantile Exchange (CME), the Chicago Board of Trade (CBOT), the New York Mercantile Exchange (NYMEX), and the Commodity Exchange (COMEX). The company owns 27% of S&P Dow Jones Indices. It is the world's largest operator of financial derivatives exchanges. Its exchanges are platforms for trading in agricultural products, currencies, energy, interest rates, metals, futures contracts, options, stock indexes, and cryptocurrencies futures.

Headquartered in Chicago, the company maintains offices in New York, Houston, and Washington D.C., in the United States, as well as abroad in Bangalore, Beijing, Belfast, Calgary, Hong Kong, London, Seoul, Singapore, and Tokyo.

The Chicago Mercantile Exchange (CME), was founded in 1898 as a nonprofit corporation. In 1919, it established its clearing house. In 2000, CME demutualized (became a joint stock company). In 2002, CME Group, the parent company of CME, became a public company via an initial public offering.

On July 12, 2007, CME Group completed a merger with the CME's historical rival, the holding company for the Chicago Board of Trade, founded in 1848, in an $8 billion deal that created the world's largest financial market. The company then launched as CME Group Inc., a CME/Chicago Board of Trade Company.

In 2012, Phupinder Gill, then CME Group's president and COO, became the company's CEO.

In November 2016, Gill retired from his role and Terrence A. Duffy, then executive chairman and president of the company, took on an expanded role as its CEO.

In 2021, the firm struck a partnership with Google to build its cloud strategy, which saw the tech giant investing $1 billion in CME Group.

In 2022, CME Group futures and options reached a record average daily volume of 23.3 million contracts.