Mumbai:  Bull operators tightened their grip on the stock market when foreign investors took a break for Christmas holidays and today  (Dec 26, 2006)lifted the benchmark Sensex by a whopping 237 points to 13,708.34 amid extremely low volume.

All indices, including sectorial, scored more than one per cent gains following across-the-board buying support.

Some leading private mutual funds too were believed to be heavy buyers in select frontline counters.

The Bombay Stock Exchange (BSE) bellwether opened strong at 13,501.44 and gradually moved upwards to the intra-day high of 13,726.62 before ending at 13,708.34, a net rise of 236.60 points or 1.76 per cent over Friday's close of 13,471.74.

The broader S&P CNX Nifty of the National Stock Exchange (NSE) too soared by 69.35 points or 1.79 per cent to close at 3,940.50 from previous close of 3,871.15.

Bulls and retail investors hectically covered their short positions ahead of the expiry of December series while a leading mutual fund was a heavy buyer in a few heavyweighted shares, brokers said.

Bear operators too were seen squaring up outstanding positions due to approaching end of the derivatives contract.

A leading mutual fund cornered large chunk of shares of blue chip companies, they added.

Mutual funds have stepped activity since last week and reported net investments of Rs 752.84 crore between December 18 and 21.

The trading volume was very low in the absence of Foreign Institutional Investors (FIIs), which were sidelined in view of year-end holidays.