As investors resorted to profit taking, after scaling the 18,000-point mark to reach its highest level in 25 months, a key Indian equity market index opened lower on Thursday.

Closing the Wednesday at 17,970.02 points, the sensitive index (Sensex) of the Bombay Stock Exchange (BSE) opened at 17,950.56 points and crawled to 17,960.91 points.

Later, with a loss of 49.90 points, or 0.28 percent, it was ruling at 17,920.12 points.

During intra-day trading on Wednesday, the index had reached 18,047.86 points, which was the highest since February 2008.

Only eight managed to trade in the green as twenty-one out of 30 stocks that comprise the Sensex were ruling lower. Among the 13 sector-specific indices, as many as eight were in the red.

The broader 50-share S&P CNX Nifty at the National Stock Exchange, was ruling at 5,360.70 points, with a loss of 13.95 points, or 0.26 percent over the previous close. (With Inputs from Agencies)