As previously announced, CME Clearing has been working for some time to support futures products with trade prices and settlement prices that can go negative, and option products with strike prices that can be negative.  (Currently, such prices can go as low as zero, but cannot go negative.)  Monday, October 1, 2007, will be the first date on which we will support such negative prices.  The first contracts that are likely to trade or settle at less than zero are the Weekly Average Temperature products.

Also as previously announced, we have been working for some time to support firm identifiers which are three-character alphanumeric values -- letters and/or numbers.  Currently, all firm ID's are composed of three numeric digits.  October 1, 2007 will be the day when we begin introducing alphanumeric firm ID's.

For the full text of this advisory . . .