TO:	ALL CLEARING PARTICIPANTS
FROM:	CLIENT SERVICES AND SUPPORT
DATE:	May 31, 2006
SUBJECT:	Chicago Climate Exchange Expiration Month Margin

The following margin change will be effective at the close of business on Wednesday May 31, 2006. :

Chicago Climate Margin Rate for June Delivery	FROM	To
Sulfur Dioxide	$2,600	$3,500

Should you have any questions, please call or e-mail one of the following Client Services and Support Representatives: