The National Association of Securities Dealers, the New York Stock Exchange and the Chicago Board Options Exchange have filed rule changes with the Securities and Exchange Commission in connection with the extension of their portfolio margining pilot programs. The pilot programs, which had been set to expire on July 31, allow qualifying members to compute customer margin requirements for eligible securities according to prescribed portfolio margining methodologies, which are intended to better estimate the actual risk of loss across the portfolio than existing strategy- or position-based margin requirements.

The pilot programs have been extended through July 31, 2008.

http://www.sec.gov/rules/sro/nyse/2007/34-56107.pdf

http://www.sec.gov/rules/sro/nasd/2007/34-56108.pdf  

http://www.sec.gov/rules/sro/cboe/2007/34-56109.pdf