News Release

CME Reduces Class A Share Requirement for Clearing Members

Wed Jan 18 2006

CHICAGO, Jan. 18 /PRNewswire-FirstCall/ -- In order to attract more participation in its markets and reduce transaction costs for existing clearing members, Chicago Mercantile Exchange Holdings Inc. (NYSE: CME)(NASDAQ: CME) today announced it will reduce the requisite number of CME Class A Shares its clearing members must acquire and hold as part of their capital investment requirement. Effective February 1, 2006, new firms applying for clearing member status will be required to acquire 15,000 shares of CME Class A stock, down from the previous requirement of 30,000 shares.

As a result of this change approximately 240,000 shares will be released each month, less than the average volume of CME stock traded in a single day. In the fourth quarter of 2005, CME shares traded an average of approximately 850,000 shares per day.

For existing CME clearing firms on or before February 1, 2006, the number of Class A shares that must be assigned to the clearing member shall be decreased incrementally by 3,000 shares per month over a five-month period.

"This change to the capital investment requirement is part of our ongoing global strategy to look for ways to reduce transaction costs and increase capital efficiencies for CME clearing firms," said CME Chairman Terry Duffy. "This plan releases approximately $6 million in additional equity capital over time for each of our current clearing firms and further implements our commitment to reduce transaction costs and increase capital efficiencies."

"By lowering the CME Class A share requirement, we continue to pursue opportunities for new firms and large market participants to use our global derivative products, as well as unlock equity value for our existing clearing member firms," said CME Chief Executive Officer Craig Donohue. "We value our strong relationships with our clearing member firms and this is another example of our commitment to building value for CME and market participants around the world."

The reduction in the required number of Class A shares clearing members must acquire is the only change CME is making to the capital investment requirements for its clearing members. All other capital investment requirements including the purchase of two CME memberships, two IMM memberships, two IOM memberships and one GEM membership, remain in effect for all clearing members of the exchange.

Chicago Mercantile Exchange Inc. ( http://www.cme.com/ ) is the world's largest and most diverse financial exchange. As an international marketplace, CME brings together buyers and sellers on CME Globex electronic trading platform and on its trading floors. CME offers futures and options on futures primarily in four product areas: interest rates, stock indexes, foreign exchange and commodities. The exchange moved about $1.4 billion per day in settlement payments in the first three quarters of 2005 and managed $43.8 billion in collateral deposits at September 30, 2005, including $3.8 billion in deposits for non-CME products. CME is a wholly owned subsidiary of Chicago Mercantile Exchange Holdings Inc. (NYSE: CME)(NASDAQ: CME), which is part of the Russell 1000® Index.

Statements in this news release that are not historical facts are forward- looking statements. These statements are not guarantees of future performance and involve risks, uncertainties and assumptions that are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed or implied in any forward-looking statements. More detailed information about factors that may affect our performance may be found in our filings with the Securities and Exchange Commission, including our most recent Quarterly Report on Form 10-Q, which can be obtained its Web site at http://www.sec.gov/ . CME undertakes no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise.

Chicago Mercantile Exchange, CME, the globe logo and CME Globex are registered trademarks of Chicago Mercantile Exchange Inc. Further information about Chicago Mercantile Exchange Holdings Inc. and Chicago Mercantile Exchange Inc. is available on the CME Web site at http://www.cme.com/ .

CME-G

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SOURCE: Chicago Mercantile Exchange Holdings Inc.

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