Tracking a firming Asian trend, the Bombay Stock Exchange benchmark index Sensex extended gains by adding over 149 points in early trade on Monday on funds-based buying in frontline stocks.

The 30-share BSE Sensex, which had gained 290.79 points on Friday, rose further by 149.93 points at 15,839.05 in first five minutes of trading, backed by a better trend in metal and realty sectors.