Following the suspension of the closing auction session (CAS) which took effect on 23 March 2009, the securities market now closes at 4pm and HKEx uses its pre-CAS method for calculating closing prices for securities (i.e. based on the median of five snapshot nominal prices taken during the last minute prior to the end of the market's afternoon session). Trading of stock index futures and options in the derivatives market ends at 4:15pm and trading of stock options and futures remains unchanged and closes at 4:00pm.

As a result of the suspension, the Electronic Disclosure publication window applicable to issuer announcements after the close of afternoon trading has been modified to 4:15pm to 11pm. Updates have also been made both to the Trading Rules of the Stock and Futures Exchanges and the Rules of the Clearing House.