News Release

CME Announces Memorial Day Holiday Hours

Tue May 23 2006

CHICAGO, May 23 /PRNewswire-FirstCall/ -- CME today announced the following trading schedule in conjunction with the Memorial Day holiday (all times are Central time):

  Friday, May 26    Commodity futures, foreign exchange (FX), interest rate,
                    and GSCI® products and weather options traded on
                    Exchange trading floors close at 12:00 p.m. (Commodity
                    options close at 12:02 p.m.)  Equity index products
                    traded on the trading floor close at their regularly
                    scheduled time of 3:15 p.m.  Equity index, interest rate
                    and FX products traded on CME® Globex® will close at
                    3:15 p.m.  Commodities, weather, fertilizer, ethanol and
                    GSCI® traded on CME Globex will close at 12 noon.
                    Products closing at their regular times on CME Globex
                    are equity indexes (3:15 p.m.), CPI (2:00 p.m.),
                    Eurozone HICP (10:00 a.m.) TRAKRS(SM) (3:00 p.m.), ETFs
                    (3:15 p.m.) and housing (2:00 p.m.).

  Sunday, May 28    CME Globex has a regular trading session opening at
                    5:00 p.m. for the trade date of Tuesday, May 30.

  Monday, May 29    Exchange trading floors closed in observance of Memorial
                    Day.  CME Globex trading continues for equity products
                    except for a 10:30 a.m. to 5:00 p.m. trading break, and
                    for interest rate and foreign exchange products except
                    for a 12:00 noon to 5:00 p.m. trading break.  CME Globex
                    traded TRAKRS and ETFs do not open on Monday, May 29.

  Tuesday, May 30   Regular trading sessions for CME Globex and Exchange
                    trading floors.

Chicago Mercantile Exchange Inc. ( http://www.cme.com/ ) is the world's largest and most diverse financial exchange. As an international marketplace, CME brings together buyers and sellers on CME Globex electronic trading platform and on its trading floors. CME offers futures and options on futures primarily in four product areas: interest rates, stock indexes, foreign exchange and commodities. The exchange managed $47.0 billion in collateral deposits at March 31, 2006, including $3.8 billion in deposits for non-CME products. CME is a wholly owned subsidiary of Chicago Mercantile Exchange Holdings Inc. (NYSE: CME)(NASDAQ: CME), which is part of the Russell 1000® Index.

Statements in this news release that are not historical facts are forward-looking statements. These statements are not guarantees of future performance and involve risks, uncertainties and assumptions that are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed or implied in any forward-looking statements. More detailed information about factors that may affect our performance may be found in our filings with the Securities and Exchange Commission, including our most recent Quarterly Report on Form 10-Q, which can be obtained at its Web site at http://www.sec.gov/ . We undertake no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise.

Chicago Mercantile Exchange, CME, the globe logo and CME Globex are registered trademarks of Chicago Mercantile Exchange Inc. E-mini is a trademark of CME. CLEARING 21 is a registered trademark of CME and New York Mercantile Exchange, Inc. S&P, S&P 500, NASDAQ-100, Nikkei 225, Russell 1000, Russell 2000, TRAKRS, Total Return Asset Contracts and other trade names, service marks, trademarks and registered trademarks that are not proprietary to Chicago Mercantile Exchange Inc. are the property of their respective owners, and are used herein under license. Further information about CME and its products is available on the CME Web site at http://www.cme.com/ .

CME-G

SOURCE: Chicago Mercantile Exchange Inc.

CONTACT: Media, Allan L. Schoenberg, +1-312-930-8189, or Mary
Haffenberg, +1-312-930-3435, news@cme.com , or Investor, John Peschier,
+1-312-930-8491, all of Chicago Mercantile Exchange Inc.

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

Corporate Communications

+1 312 930 3434
Email