Exhibit 99.1

FOR IMMEDIATE RELEASE

CME GROUP AND GFI GROUP RECEIVE REGULATORY APPROVALS FOR REVISED

TRANSACTION; SPECIAL MEETING OF GFI STOCKHOLDERS SCHEDULED FOR

JANUARY 27, 2015

LONDON, CHICAGO and NEW YORK, January 5, 2015 — CME Group Inc., the world’s leading and most diverse derivatives marketplace, and GFI Group Inc., a leading intermediary and provider of trading technologies and support services to the global OTC and listed markets, today announced that they have received all of the material regulatory approvals necessary to close the previously announced acquisition of GFI Group by CME. The transaction remains subject to the approval of GFI Group’s stockholders; GFI Group will hold a special meeting of its stockholders on January 27, 2015 to vote on the transaction.

“With these regulatory approvals and the significant shareholder support through commitments from Jersey Partners Inc., GFI Group’s largest stockholder, we believe the planned merger of CME Group and GFI Group can deliver value with speed and certainty for all GFI Group shareholders,” said GFI Group Executive Chairman, Michael Gooch.

The revised transaction has been approved by the Board of Directors of GFI Group upon the unanimous recommendation of a Special Committee comprised solely of independent and disinterested directors, and by the Board of Directors of CME Group. The transaction is expected to close shortly following the stockholders’ meeting.

About CME Group

As the world’s leading and most diverse derivatives marketplace, CME Group (www.cmegroup.com) is where the world comes to manage risk. CME Group exchanges offer the widest range of global benchmark products across all major asset classes, including futures and options based on interest rates, equity indexes, foreign exchange, energy, agricultural commodities, metals, weather and real estate. CME Group brings buyers and sellers together through its CME Globex^® electronic trading platform, its trading facilities in New York and Chicago, and through its London-based CME Europe derivatives exchange. CME Group also operates one of the world’s leading central counterparty clearing providers through CME Clearing and CME Clearing Europe, which offer clearing and settlement services across asset classes for exchange-traded contracts and over-the-counter derivatives transactions. These products and services ensure that businesses everywhere can substantially mitigate counterparty credit risk.

CME Group is a trademark of CME Group Inc. The Globe Logo, CME, Globex and Chicago Mercantile Exchange are trademarks of Chicago Mercantile Exchange Inc. CBOT and the Chicago Board of Trade are trademarks of the Board of Trade of the City of Chicago, Inc. NYMEX, New York Mercantile Exchange and ClearPort are registered trademarks of New York Mercantile Exchange, Inc. COMEX is a trademark of Commodity Exchange, Inc. All other trademarks are the property of their respective owners. Further information about CME Group (NASDAQ: CME) and its products can be found at www.cmegroup.com.

About GFI Group Inc.

GFI Group Inc. (NYSE: GFIG) is a leading intermediary in the global OTC and Listed markets offering an array of sophisticated trading technologies and products to a broad range of financial market participants. More than 2,500 institutional clients benefit from GFI’s know-how and experience in operating electronic and hybrid markets for cash and derivative products across multiple asset classes, including fixed income, interest rates, foreign exchange, equities, energy and commodities. GFI’s brands include Trayport^®, a leading provider of trading solutions for energy markets worldwide and FENICS^®, a market leader in FX options software.

Founded in 1987 and headquartered in New York, GFI employs over 2,000 people globally, with additional offices in London, Paris, Brussels, Nyon, Dublin, Madrid, Sugar Land (TX), Hong Kong, Tel Aviv, Dubai, Seoul, Tokyo, Singapore, Sydney, Cape Town, Santiago, Bogota, Buenos Aires, Lima and Mexico City.

Media Contacts

Patricia Gutierrez

GFI Group Vice President — Public Relations

+ 1 212 968 2964

patricia.gutierrez@gfigroup.com

Laurie Bischel

CME Group Executive Director, Corporate Communications

+1 312 907 0003

Laurie.Bischel@cmegroup.com

Investor Contacts

Mark Brazier

GFI Group Senior Vice President, Corporate Development and Communications

+1 212 968 6905

mark.brazier@gfigroup.com

Chris Ann Grimmett

GFI Group Investor Relations Manager

+1 212 968 4167

chris.grimmett@gfigroup.com

John Peschier

CME Group Managing Director, Investor Relations

+1 312 930 8491

John.Peschier@cmegroup.com

Important Information for Investors and Stockholders

In connection with the proposed transaction between GFI and CME, on December 24, 2014 the Securities and Exchange Commission (SEC) declared effective CME’s registration statement on Form S-4 that included a definitive proxy statement of GFI that also constituted a definitive prospectus of CME. On December 24, 2014, GFI commenced mailing the definitive proxy statement/prospectus to stockholders of GFI. INVESTORS AND SECURITY HOLDERS OF GFI ARE URGED TO READ THE DEFINITIVE PROXY STATEMENT/PROSPECTUS (INCLUDING ALL AMENDMENTS AND SUPPLEMENTS THERETO) AND OTHER DOCUMENTS FILED WITH THE SEC, CAREFULLY AND IN THEIR ENTIRETY BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION. Investors and security holders may obtain free copies of the registration statement and the definitive proxy statement/prospectus and other documents filed with the SEC by CME and GFI through the website maintained by the SEC at http://www.sec.gov or at the SEC public reference room at 100 F Street N.E., Room 1580, Washington, D.C. 20549. Please call the SEC at (800) 732-0330 or visit the SEC’s website for further information on its public reference room. Copies of the documents filed with the SEC by GFI are available free of charge on GFI’s website at http://www.gfigroup.com or by contacting GFI’s Investor Relations Department at (212) 968-4167. Copies of the documents filed with the SEC by CME are available free of charge on CME’s website at http://www.cmegroup.com or by contacting CME’s Investor Relations Department at (312) 930-8491.

Participants in the Solicitation for the Proposed Merger Between GFI and CME

GFI and its directors, executive officers and certain of its employees may be considered participants in the solicitation of proxies in connection with the proposed transactions involving GFI and CME. Investors and security holders may obtain more detailed information regarding the names, affiliates and interests of GFI’s directors and executive officers by reading GFI’s Annual Report on Form 10-K for the year ended December 31, 2013, which was filed with the SEC on March 13, 2014, its proxy statement for its 2014 annual meeting of stockholders, which was filed with the SEC on April 22, 2014, and its Current Report on Form 8-K filed with the SEC on July 25, 2014. These documents can be obtained free of charge from the sources indicated above. Additional information regarding the participants in the proxy solicitations and a description of their direct and indirect interests, by security holdings or otherwise, is or will be contained in the proxy statement/prospectus and other relevant materials filed with the SEC. This press release 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 appropriate registration or qualification under the securities laws of 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.

Cautionary Statement Regarding Forward-Looking Statements

Certain matters discussed in this press release contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to (i) plans, objectives, expectations and intentions; (ii) other statements contained in this communication that are not historical facts; and (iii) other statements identified by words such as “anticipate,” “believe,” “estimate,” “may,” “might,” “intend,” “expect” and similar expressions. Actual results, performance or achievements could differ materially from those contemplated, expressed or implied by the forward-looking statements contained herein. These forward-looking statements are based largely on the expectations of GFI and are subject to a number of risks and uncertainties. These include, but are not limited to, risks and uncertainties associated with: the occurrence of any event, change or other circumstances that could give rise to the termination of the definitive agreements involving GFI and CME; the inability to complete the proposed merger involving GFI and CME due to the failure to obtain the required stockholder approval; the inability to satisfy the other conditions to the closing of the proposed merger involving GFI and CME or the tender offer by BGC, including without limitation the receipt of necessary governmental or regulatory approvals required to complete either transaction; the risk that either transaction disrupts current plans and operations and/or increases operating costs and the potential difficulties in customer loss and employee retention as a result of the announcement and consummation of either transaction; the outcome of any legal proceedings that may be instituted against GFI, CME, BGC or others following announcement of either transaction; economic, political and market factors affecting trading volumes; securities prices or demand for GFI’s brokerage services; competition from current and new competitors; GFI’s ability to attract and retain key personnel, including highly-qualified brokerage personnel; GFI’s ability to identify and develop new products and markets; changes in laws and regulations governing GFI’s business and operations or permissible activities; GFI’s ability to manage its international operations; financial difficulties experienced by GFI’s customers or key participants in the markets in which GFI focuses its services; GFI’s ability to keep up with technological changes; and uncertainties relating to litigation and GFI’s ability to assess and integrate acquisition prospects. Further information about factors that could affect the financial and other results of GFI is included in its filings with the SEC. GFI undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

These forward-looking statements speak only as of the date hereof. Except for the ongoing obligations of GFI to disclose material information under the federal securities laws, GFI undertakes no obligation to revise or update publicly any forward-looking statement, except as required by law. Other factors that may impact the forward-looking statements are described in GFI’s annual report on Form 10-K for the fiscal year ended December 31, 2013 and Forms 10-Q. For additional information on GFI, please visit GFI’s website at http://www.gfigroup.com.

CME-G

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