ISS and Egan-Jones also recommend CME Group shareholders vote 'FOR' the

                                transaction



    NEW YORK, Aug. 6 /EMWNews/ -- NYMEX Holdings, Inc. (NYSE:

NMX), parent company of the New York Mercantile Exchange, Inc., today

announced that Institutional Shareholder Services Inc. (ISS) and Egan-Jones

Proxy have recommended that NYMEX shareholders vote "FOR" the acquisition

by CME Group. In separate reports, ISS and Egan-Jones also recommended that

NYMEX and CME Group shareholders vote "FOR" the transaction.



    In recommending that NYMEX shareholders vote to approve the

acquisition, ISS stated that, "Based on our review of the terms of the

transaction and ... in particular the strategic rationale of the

transaction, we believe that the merger agreement warrants shareholder

support."



    Egan-Jones' review centered on the strategic and financial aspects of

the proposed transaction in the context of maximizing shareholder value.



    *Permission to use quotations from the ISS report was neither sought

nor obtained.

    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(R) electronic platform, as well as clearing off-exchange

instruments through NYMEX ClearPort(R) 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.



    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 results 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 Holdings' 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

definitive joint proxy statement/prospectus. This press release is not a

substitute for the definitive joint proxy statement/prospectus or any other

documents CME Group and NYMEX Holdings have filed or will file with the

SEC. Investors and security holders are urged to read the definitive joint

proxy statement/prospectus and any other relevant documents filed or to be

filed by CME Group or NYMEX Holdings because they contain or will contain

important information about the proposed transaction. The definitive joint

proxy statement/prospectus and other documents filed or to be filed by CME

Group or NYMEX Holdings 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.