SecProbe.io

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

       DIVISION OF
CORPORATION FINANCE
Mail Stop 3010

July 14, 2009
 Mr. James E. Parisi  Managing Director and Ch ief Financial Officer
CME Group Inc. 20 South Wacker Drive Chicago, Illinois 60606
 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 response in connection with the above-referenced filings
and have the following comments.  Where i ndicated, we think you should revise your
document in response to these comments.  If you disagree, we will consider your
explanation as to why our comment is inappl icable or a revision is unnecessary.  Please
be as detailed as necessary in your explanat ion.  In some of our comments, 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.

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

Compensation Discussion and Analysis
 Base Pay, page 28

1. We note that you plan to expand your disclo sure in future filings to discuss the
individual factors considered by the Compensation Committee in determining
annual salary increases; however, you have not explained why Mr. Parisi received

Mr. James E. Parisi
CME Group Inc. July 14, 2009 page 2

such an increase.  Please provide to us in your response letter the specific factors
that led to Mr. Parisi’s salary increase.
 Equity Grant Practices, page 33

2. We note your response to prior comment 8 and reissue that comment.  It remains
unclear from your current disclosure how the pre-established formulas are derived
from the various factors discussed on page 34 under the Compensation and
Discussion  subheading, per your response.  Plea se revise your disclosure to
provide a more in-depth discussion of thes e formulas and also provide an analysis
of how the formulas contributed to the equity awards granted to each of the
named officers in 2008.
 Management Equity Opportunities, page 34

 3. Your response to previous Comment 9 tie s the established targets for your named
executives to the benchmarking process, but, as currently written, your discussion
of benchmarks does not adequately provi de investors with a clear understanding
of how these targets are establishe d.  Please revise or advise.

*****
   As appropriate, please amend your fili ng 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;

Mr. James E. Parisi
CME Group Inc. July 14, 2009 page 3

‚ 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 at (202) 551- 3473 with any questions.

Sincerely,

        T o m  K l u c k          B r a n c h  C h i e f    cc: Margaret C. Austin (via facsimile)