In response to clearing firms’ requests, beginning Friday, March 2 2007, changes will be implemented in Front End Clearing (FEC) for CBOT FLEX Options only. With this change, FEC deadline to submit CBOT FLEX post-trade activity will be 4:00 p.m. CST. Also, the deadline to submit CBOT FLEX exercises, contrary instructions, PCS, and position adjustments will be 5:00 p.m. CST.

Also, effective with this change, CBOT FLEX Options only will have exercise and assignment based on a pro-rata algorithm. All other non-CBOT FLEX products will retain the random algorithm for exercise and assignment processing. The Clearing deadlines for all non-CBOT FLEX products will remain unchanged.

The Clearing House will update the Submitted Special Options Exercise Instruction Report at 5:00 p.m. which will include FLEX contrary instructions, and again at 6:00 p.m. including all CBOT options products.

Clearing Firms will be given the details of CBOT FLEX Exercise/Assignment activity by 6:00 p.m. An INFOPAC/Document Direct Report (CPM651) CBOT FLEX Exercise/Assignment notice will be made available by 6:00 p.m.

For questions or concerns, please contact CME Clearing House at 312-207-2525 or via email toccs@cme.com.

Thank you