Stocks in India snapped a three-day down trend on Thursday but not without experiencing extremes in volatility that saw the benchmark Sensex Index swing 500 points intraday. Traders appear to be putting aside any negative sentiment created by the fuel price hike and snapping up stocks they deem to be undervalued. The Sensex Index had plunged more than 900 points over the past three trading sessions."There is a lot of volatility in the market. Unless it gains some stability, it is difficult to take a call on the direction. Nevertheless, valuations are attractive at this stage," said Jignesh Shah of ABN Amro Bank. The Bombay Stock Exchange's Sensex Index slipped 254.93 points, or 1.64%, to 15,769.72. Here's a look at how some India-based American depositary shares traded in the U.S. on Thursday. Stifel Nicolaus & Company said it will keep its hold rating on shares of Infosys Technologies ( INFY) but raise its estimates for the Indian information technology firm. In a note to clients a Stifel analyst said due to the Indian government's approval of a one-year extension of the software technology park tax exemption, it is raising its EPS estimates for 2009 from $2.47 to $2.54 and for 2010 from $2.79 to $2.82. American depositary shares of Infosys, which trade on the Nasdaq, surged 5.7% to $49.37. Stifel Nicolaus & Company also reiterated its buy rating for U.S.-based information technology provider Cognizant Technology Solutions ( CTSH) and set its price target at $41. Stifel raised its EPS estimates for 2009 from $1.74 to $1.93 and for 2010 from $2.15 to $2.16, citing the software technology park tax exemption. Cognizant has a large exposure to the Indian technology market. Shares of Cognizant moved up 3.5% to $36.78.