We would like to take this opportunity to remind you of an important upcoming change to the ITC 2.1 channels on the CME® Market Data Platform (MDP). Currently, there are 4 channels designated for ITC data, exclusively. As CME continues to see growth in trading volume, message rates are continually growing as well. As such, it has become increasingly evident that the current 4 ITC channels need to be scaled out horizontally for improved efficiency in the delivery of market data.

While the addition of more ITC channels is the long term approach towards which CME is moving, the short term approach will be to conduct load balancing across two of the existing channels. We will be taking the following actions:

• CME E-mini Russell 2000® Options (ticker symbol ER) and CME E-mini S&P 500® Options (ticker symbol ES) will be removed from Channel 5 - CME Globex® Options Top of Book - of the Market Data Platform
• These options will be added to Channel 6 - CME Globex Spreads Top of Book - of the Market Data Platform

For a complete list of IP addresses and Ports for the MDP, please consult the CME Developer’s Guide which can be accessed through the following link: http://www.cme.com/files/MDPProdChannelDefs.pdf

These changes will go into production beginning January 21, 2007. Saturday testing will be available on 01/20/07. (previous Saturday tests were held on 12/16/06 & 01/06/07)

Saturday testing will be conducted from 7:30am until 11:30am CDT. If you encounter any issues during this test please call 312.656.0595.

If you have any questions or concerns, please contact Kevin Brady at 312.648.3653

Thank you.