Dear CME Globex Customers,

Effective May 7, 2006 (for trade date May 8), CME is scheduled to launch the new CME Options Auto-Reserve functionality.

Whenever an outright Lead Month Futures instrument in Continuous Trading state is put in Reserved state, the CME Options Auto-Reserve functionality automatically places the corresponding options and option spreads into a temporary Interrupted state. Customers can submit, modify and cancel orders during the Reserved and Interrupted states.

Please note: when the CME Options Auto-Reserve places an instrument group in Interrupted State, all resting quotes will be cancelled and all new Mass Quote messages will be rejected until the group is returned to Continuous Trading state.

The Group State (MJ) market data message will be disseminated with the value "Z" in position 52 when the CME Options Auto-Reserve places an options instrument group into Interrupted state. As a reminder, the value "AR" in position 86-87 of the Instrument State (MG) message indicates that an instrument has been put in Reserved state, as detailed in CME Market Data Platform RLC Message Specifications.

If you have any questions or concerns, please contact your CME Globex Account Manager at 312.634.8700, or in Europe at +44.207.623.2550.

Thank you,

CME