Investors opting for fresh positions on beginning of February derivatives supported by data showing that FIIs have been indulged in intense buying.
The Sensex opened higher at 27,761.03 and moved in a range of 27,950.33 and 27,759.48, before quoting 27,949.31 at 1040 hrs, showing a gain of 241.17 points or 0.87 per cent.
The NSE 50-share Nifty was also higher by 63.25 points, or 0.74 per cent, at 8,666.00 at 1040 hrs.
Meanwhile, the foreign portfolio investors (FPIs) bought shares worth a net Rs 1,378.81 crore on Wednesday, as per provisional data released by the stock exchanges.
Overseas, Asian markets were trading higher. The US markets closed on a mixed note yesterday.