Mumbai :  India's benchmark stock index fell, snapping four days of gains, led by HDFC Bank Ltd on concern this month's advance outpaced prospects for earnings growth.

HDFC Bank, whose shares rose to a record yesterday, lost the most in more than two months on concern a surge in the company's relative strength index signalled the end of the rally. Software exporter Infosys Technologies Ltd dropped for the third day after the rupee touched an 18-month high against the dollar, paring the value of earnings generated overseas.

"Investors should book partial profit" in HDFC Bank, said Vasudeo Mileen Kamlakant, a technical analyst at Angel Broking Ltd., India's biggest brokerage by distribution network, according to Dun & Bradstreet. "It is a sign of cautiousness as it is in the overbought zone."

The Bombay Stock Exchange's Sensitive Index, or Sensex, fell 121.18, or 0.7 per cent, to 17,590.17. Its 14-day relative strength index, measuring how rapidly prices rose or fell during the period, exceeded 70 over the past two trading days.

Some investors see readings above 70 as a signal to sell. The gauge, which closed at a two-year high yesterday, has advanced 7.1 per cent this month, set for its biggest monthly gain since November. The index is poised for a fifth quarterly increase, its best stretch since the third quarter of 1994.

The S&P CNX Nifty Index on the National Stock Exchange lost 0.8 per cent to 5,262.45. The BSE 200 Index retreated 0.5 per cent to 2,202.91.