Mumbai: Amid weak trend on Asian bourses, Bombay Stock Exchange index Sensex fell by nearly 150 points in opening trade on Thursday on selling by funds ahead of the RBI monetary policy.

The 30-share barometer that gained 191.05 points in the previous session, dropped by 149.64 points to 18,209.05, with banking, auto, realty and IT stocks leading the fall.

In a similar fashion, the broad-based National Stock Exchange index Nifty lost 57.25 points, to 5,453.90 points in the first few minutes of the trade.

Brokers said besides a weakening trend on Asian bourses following overnight losses at the US market, off-loading of positions by speculators on fears that the RBI may announce a
hike in key rates in its monetary policy review later on Thursday further dampened the sentiments.

Meanwhile, Key Asian indices -- Hong Kong's Hang Seng and Japan's Nikkei-- were trading in red by 2.18 per cent and 2.09 per cent,respectively, in the morning trade on Thursday.