News Release

CME Group Inc. and NYMEX Holdings, Inc. to Mail Joint Proxy Statement/Prospectus for August 18, 2008 Vote on Proposed Merger

Mon Jul 21 2008

CHICAGO, July 21 /PRNewswire-FirstCall/ -- CME Group Inc. (NASDAQ: CME) and NYMEX Holdings, Inc. (NYSE: NMX) today announced that they will begin mailing a definitive joint proxy statement today to shareholders of record as of the close of business on July 18, 2008. The companies also announced that the U.S. Securities and Exchange Commission has declared effective the Registration Statement on Form S-4 relating to CME Group's proposed acquisition of NYMEX.

CME Group will hold a special shareholder meeting on August 18, 2008, at the Union League Club of Chicago, located at 65 West Jackson in Chicago at 3:00 p.m., Central Time. Also on August 18, 2008, NYMEX will hold a special member meeting at 3:00 p.m., Eastern Time and a special shareholder meeting at 4:00 p.m., Eastern Time, both located at the New York Mercantile Exchange, One North End Avenue, World Financial Center.

The transaction is subject to approvals of shareholders of both companies and of NYMEX Class A members. Changes in Class A member rights associated with the transaction will be accomplished through amendments to the certificate of incorporation and bylaws of NYMEX which require the affirmative vote of the owners of 75 percent of the outstanding NYMEX Class A memberships. The approval of these amendments is a condition to the closing of the merger.

The CME Group Board of Directors has recommended that its shareholders vote "for" the proposal to approve the Third Amended and Restated Certificate of Incorporation and "for" the proposal to approve the issuance of CME Group Class A common stock to NYMEX Holdings shareholders pursuant to the merger agreement. The NYMEX Holdings, Inc. Board of Directors has recommended that its shareholders vote "for" the proposal to approve the transaction.

Subject to obtaining the necessary approvals, the companies expect to close the merger in the third quarter of 2008. The joint proxy statement/prospectus is available at: http://www.sec.gov/, http://www.cmegroup.com/ and http://www.nymex.com/.

About CME Group

CME Group (http://www.cmegroup.com/) is the world's largest and most diverse exchange. Formed by the 2007 merger of the Chicago Mercantile Exchange (CME) and the Chicago Board of Trade (CBOT), CME Group serves the risk management needs of customers around the globe. As an international marketplace, CME Group brings buyers and sellers together on the CME Globex electronic trading platform and on its trading floors. CME Group offers the widest range of benchmark products available across all major asset classes, including futures and options based on interest rates, equity indexes, foreign exchange, agricultural commodities, and alternative investment products such as weather and real estate. CME Group is traded on the NASDAQ under the symbol "CME."

About NYMEX Holdings, Inc.

NYMEX Holdings, Inc. (NYSE: NMX) is the parent company of New York Mercantile Exchange, Inc., the world's largest physical commodities exchange, offering futures and options trading in energy, metals and other contracts and clearing services for more than 400 off-exchange contracts. Through a hybrid model of open outcry floor trading and electronic trading on the CME Globex® electronic platform, as well as clearing off-exchange instruments through NYMEX ClearPort® Clearing, NYMEX offers crude oil, petroleum products, natural gas, coal, electricity, gold, silver, copper, aluminum, platinum group metals, emissions, and soft commodities contracts for trading and clearing virtually 24 hours each day. Further information about NYMEX Holdings, Inc. and the New York Mercantile Exchange, Inc. is available on the NYMEX website at http://www.nymex.com/.

Additional Information Forward Looking Statements:

This press release may contain forward-looking information regarding CME Group Inc. ("CME Group") and NYMEX Holdings, Inc. ("NYMEX Holdings") and the combined company after the completion of the merger that are intended to be covered by the safe harbor for "forward-looking statements" provided by the Private Securities Litigation Reform Act of 1995. These statements include, but are not limited to, the benefits of the business combination transaction involving CME Group and NYMEX Holdings, including future financial and operating results, the new company's plans, objectives, expectations and intentions and other statements that are not historical facts. Such statements are based on current beliefs, expectations, forecasts and assumptions of CME Group's and NYMEX Holdings' management which are subject to risks and uncertainties which could cause actual outcomes and result to differ materially from these statements. Other risks and uncertainties relating to the proposed transaction include, but are not limited to the satisfaction of conditions to closing; including receipt of shareholder, antitrust, regulatory and other approvals on the proposed terms and schedule; the proposed transaction may not be consummated on the proposed terms and schedule; uncertainty of the expected financial performance of CME Group following completion of the proposed transaction; CME Group may not be able to achieve the expected cost savings, synergies and other strategic benefits as a result of the proposed transaction or may take longer to achieve the cost savings, synergies and benefits than expected; the integration of NYMEX Holdings with CME Group's operations may not be successful or may be materially delayed or may be more costly or difficult than expected; general industry and market conditions; general domestic and international economic conditions; and governmental laws and regulations affecting domestic and foreign operations.

For more information regarding other related risks, see Item 1A of CME Group's Annual Report on Form 10-K for the fiscal year ended December 31, 2007 and Item 1A of NYMEX's Annual Report on Form 10-K for the fiscal year ended December 31, 2007 and additional updates to these risks contained in our Quarterly reports. Copies of said 10-Ks and 10-Qs are available online at http://www.sec.gov/ or on request from the applicable company. You should not place undue reliance on forward-looking statements, which speak only as of the date of this press release. Except for any obligation to disclose material information under the Federal securities laws, CME Group and NYMEX Holdings undertake no obligation to release publicly any revisions to any forward- looking statements to reflect events or circumstances after the date of this press release.

Important Merger Information

In connection with the merger transaction involving CME Group and NYMEX Holdings, CME Group has filed a registration statement on Form S-4 with the Securities and Exchange Commission ("SEC") on July 21, 2008 containing a final joint proxy statement/prospectus. Investors and security holders are urged to read the final prospectus/proxy statement and any other such documents, when available, which will contain important information about the proposed transaction. The final prospectus/proxy statement and other documents filed or to be filed by CME Group with the SEC are or will be available free of charge at the SEC's Web site ( http://www.sec.gov/ ) or from CME Group Inc., Attention: Shareholder Relations, 20 S. Wacker Drive, Chicago, Illinois 60606, (312) 930-1000 or NYMEX Holdings, Inc., Attention: Investor Relations, at One North End Avenue, World Financial Center, New York, New York 10282, (212) 299-2000.

CME Group and NYMEX Holdings and their respective directors, executive officers and other members of management and employees may be deemed to be participants in the solicitation of proxies from CME Group and NYMEX Holdings shareholders in respect of the proposed transaction. Information regarding CME Group and NYMEX Holdings' directors and executive officers is available in their respective proxy statements for their 2008 annual meeting of stockholders. Additional information regarding the interests of such potential participants is included in the joint proxy statement/prospectus and the other relevant documents filed with the SEC when they become available. This document shall not constitute an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offering of securities shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.

CME-G

SOURCE: CME Group Inc.

CONTACT: Press Inquiries, Allan Schoenberg, +1-312-930-8189,
news@cmegroup.com, or Investors, John Peschier, +1-312-930-8491, both of CME
Group Inc.; or Press Inquiries, Anu Ahluwalia, +1-212-299-2439,
pressoffice@nymex.com, or Investors, Keil Decker, +1-212-299-2209, both of
NYMEX

Web site: http://www.cme.com/

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