SecProbe.io

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549-7010

       DIVISION OF
CORPORATION FINANCE
Mail Stop 3010
        May 5, 2009  Mr. James E. Parisi  Managing Director and Ch ief Financial Officer
CME Group Inc. 20 South Wacker Drive Chicago, Illinois

Re: CME Group Inc.
 Form 10-K for the fiscal year ended December 31, 2008
Filed March 2, 2009  Definitive Proxy Statement on Schedule 14A
Filed March 31, 2009
 File No. 001-31553
Dear Mr. Parisi:
 We have reviewed your above-referen ced filings and have the following
comments.  Where indicated, we think you shoul d revise your documents in response to
these comments.  If you disagree, we will consider your explanation as to why our
comment is inapplicable or a revision is unneces sary.  Please be as detailed as necessary
in your explanation.  In some of our comme nts, we may ask you to provide us with
information so we may better understand your  disclosure.  After reviewing this
information, we may raise additional comments.   Please understand that the purpose of our re view process is to assist you in your
compliance with the applicable disclosure  requirements and to  enhance the overall
disclosure in your filing.  We look forward to  working with you in these respects.  We
welcome any questions you may have about our  comments or any other aspect of our
review.  Feel free to call us at the telephone numbers listed at the end of this letter.

Form 10-K for the fiscal year ended December 31, 2008

Item 5.  Market for Registrant’s Common E quity, Related Stockholder Matters and Issuer
Purchases of Equity Securities
 Dividends, page 42

 1. In future filings, please provide more de tailed disclosure regarding the provisions
of your existing credit facility which mate rially limit your ability to pay dividends
or advise us why such revision is not necessary.  Refer to Item 201(c)(1) of
Regulation S-K.

James E. Parisi
CME Group Inc.
May 5, 2009
Page 2

Item 7.  Management’s Discussion and Analys is of Financial Condition and Results of
Operations
 Results of Operations, page 55

 2. Please expand this section to discuss known material trends and uncertainties that
will have, or are reasonably likely to have, a material impact on your revenues or income in any material way.  For example,  we note your disclosure on page 6 of
the business section regard ing the decline of open in terest of CME and CBOT
during 2008 and the risk factor on page 32 regarding the de crease in trading
volume of Eurodollar options contracts in  2008.  We also note your disclosure in
the MD&A section on pages 48 and 56-59 that  discusses the decrease in trading
volume for certain products in 2008.  In fu ture filings, please revise your MD&A
discussion to address this trend and the resulting impact on revenues and
operating income, or tell us why you believe  it is not a material trend.  Refer to
Item 303(a)(3)(i) and (ii) of Regulation S-K.

Operating Revenues, page 56

 3. Please note that you should disclose in quantitative terms the extent to which
changes in revenues from one period to th e next were attributable to changes in
prices as opposed to changes in volume.   Please ensure that you address these
matters in future filings.  Refer to Item 303(a)(3)(iii) of Regulation S-K.

Definitive Proxy Statement on Sc hedule 14A filed on March 31, 2009

Corporate Governance, page 15
4. In future filings, please disclose whether you have adopted a code of ethics that
applies to your principal executive, principal financial officer, principal
accounting officer or controll er, or persons performing similar functions per the
requirements set forth in Item  406(a) or Regulation S-K.

Compensation Discussion and Analysis
 Overview, page 24

5. Please be advised that the Compensati on Discussion and Analysis should be
sufficiently precise to identify material di fferences in compensation policies with
respect to individual executive officers . For instance, we note that there are
appreciable differences between the levels  of compensation (e.g. base salary and
non-equity incentive plan compensation)  received by your named executives. In
future filings, please explain the reasons  for the differences in the amounts of
compensation awarded to the named executive officers.

James E. Parisi
CME Group Inc.
May 5, 2009
Page 3

Base Pay, page 28
6. We note that individual base salaries are intended to be appropriate in light of the
nature and responsibility of the respective positions.  In future filings, please
include the specific individual factors that the compensation committee considered in determining annual salary increases.  For instance, we note on page
42 that Mr. Parsi received an increase in salary while the other executives’ salaries remained unchanged.  Refer to Item 402(b)(2)(v) of Regulation S-K.
Please tell us how you intend to comply.

Bonus, page 29

7. We note your reference to a pre-determ ined cash earnings target of $912 million
that was used to determine the cash  bonus amounts payable to your named
executive officers; however, it is not clea r from your disclosure what specific
goals for each named executive officer re quired achievement in order to receive
the bonus payment. In future filings, pl ease include the analysis used by the
committee to determine each executive’s individual performance of the pre-
established objectives.  We also note the additional metric of anticipated synergy
targets resulting from your complete d mergers, which was considered in
connection with the bonus payment.  Al so, include the pre-determined merger-
related milestones for the year and expl ain whether each of the named executive
officers had different syne rgy savings targets as part of such officer’s
performance evaluation.  Refer to Item 402(b)(2)(v) and Instruction 4 to Item
402(b) and Item 402(b)(2)(vii) of Regulati on S-K.  Please tell us how you intend
to comply.

Equity Grant Practices, page 33
8. We note on page 44 under the Grants of Plan-Based Awards  table that the
approved 2008 equity grants were base d on pre-established formulas under your
equity program.  In future filings, please  expand your disclosure to include such
formulas or, alternatively, explain w hy you believe such disclosure is not
material.

Senior Management Equity Opportunities, page 34
9. In future filings, please expand your disclo sure to include the specific individual
objectives that the compensation committ ee considered in determining equity
opportunities.  Please describe how the targ ets were derived and discuss in more
detail the actual performance of each executi ve relative to the targets.  Refer to
Item 402(b)(2)(vii) of Regulation S-K.  Pl ease tell us how you intend to comply.

*****

James E. Parisi
CME Group Inc.
May 5, 2009
Page 4

 As appropriate, please amend your filings  and respond to these comments within
10 business days or tell us when you will provid e us with a response.  You may wish to
provide us with marked copies of the amendm ent to expedite our review.  Please furnish
a cover letter with your amendment that keys your responses to our comments and
provides any requested information.  Detailed co ver letters greatly faci litate our review.
Please understand that we may have addi tional comments after reviewing your
amendment and responses to our comments.    We urge all persons who are responsi ble for the accuracy an d adequacy of the
disclosure in the filing to be certain that the filing includes all in formation required under
the Securities Exchange Act of 1934 and th at they have provided all information
investors require for an informed invest ment decision.  Since the company and its
management are in possession of all facts re lating to a company’s disclosure, they are
responsible for the accuracy and adequacy of the disclosures they have made.
  In connection with responding to our comments, please provide, in writing, a
statement from the company acknowledging that:  ‚ the company is responsible for the adequacy  and accuracy of the disclosure in the
filing;
‚ staff comments or changes to disclosure  in response to staff comments do not
foreclose the Commission from taking any action with respect to the filing; and

‚ the company may not assert staff comments as a defense in any proceeding initiated
by the Commission or any person under the federal securities laws of the United States.

In addition, please be advise d that the Division of Enfo rcement has access to all
information you provide to the staff of the Divi sion of Corporation Fi nance in our review
of your filing or in response to our comments on your filing.

 Please contact Jerard Gibson, Attorn ey-Advisor, at (202) 551-3473 or the
undersigned with any questions.
Sincerely,

Tom Kluck  Branch Chief
 cc: Margaret C. Austin (via facsimile)