Mumbai, (Agencies): Marketmen said the sentiment was also affected by the widening probe in the 2G spectrum allocation scam, pulling down ADAG firm RCom by nearly 7 per cent.

The Bombay Stock Exchange benchmark Sensex, which rallied nearly 1,045 points during the five-session bull-run, fell sharply by 295.30 points, or 1.60 per cent to close at 18,211.52 after touching a low of 18,159.82 largely on fag-end sell-off.

The gauge gained nearly 186 points at one stage to hit a high of 18,690.97 points on the back of sustained surge in realty, banking and oil and gas sector stocks supported by easing inflation.

The wide-based National Stock Exchange index Nifty also lost 87.50 points, 1.58 per cent to 5,458.95, after touching the day's low of 5,441.95.

Marketmen said emergence of profit-taking by funds as well as retail investors after witnessing significant gains in mainly dampened the trading sentiment.

Retail investors, who had been extending support to the market in the past few sessions, turned cautious and reduced their portfolio ahead of the monthly expiry next week and the general Budget for the financial year 2011-12.

In 30-BSE index components, 25 stocks ended with losses while 5 closed higher.

Stocks of RCom tumbled 6.80 per cent to Rs 93.15 on massive selling, triggered by ongoing CBI probe into the 2G spectrum allocation scam.

The realty sector index suffered the most by falling 4.04 per cent to 2,052.11 followed by auto sector index by 2.39 per cent to 8,717.71.

The oil and gas index plunged 2.09 per cent to 9,329.99 and capital goods sector index by 1.97 per cent to 13,132.51.

The banking index fell by 1.73 per cent to 12,419.72 as largest lenders State Bank of India and ICICI Bank suffered fresh losses.

With the selling spread over a broad front, the small-cap index closed 2.35 per cent lower at 8,128.91 points, while mid-cap index shed 1.98 per cent to 6,661.65.