Pre-open trade session is a 15 minute trade session from 9:00AM to 9:15AM on the 50 stocks of NIFTY index to reduce the volatility.
This was introduced on Indian stock market from 18th Oct 2010 onwards. Both NSE and BSE will have a 15 minute ‘pre-open session call auction’ from 9:00AM to 9:15AM.
Only 50 stocks of the NIFTY index can be traded during this time on both NSE and BSE. Normal trading for all other stocks will start at 9:15AM till 3:30PM.