TO:	ALL CLEARING PARTICIPANTS
FROM:	CLIENT SERVICES AND SUPPORT
DATE:	March 17, 2006
SUBJECT:	Chicago Climate Exchange Calendar Spread Margin Rate

The following spread credits in the Sulfur Dioxide will be effective start of business Monday March 20, 2006:

	Jun 06	Sept 06	Dec 06	Mar 07	Jun 07	Dec 07
Sept 06	50%
Dec 06	50%	50%
Mar 07	50%	50%	50%
Jun 07	50%	50%	50%	50%
Dec 07	50%	50%	50%	50%	50%
Dec 08	50%	50%	50%	50%	50%	50%

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