* Tech shares weak after Infosys cuts sales forecast
* P&G and Merck cut Dow's loss
* S&P holding onto support at 50-day moving average
* Dow off 0.3 pct, S&P off 0.5 pct, Nasdaq off 0.8 pct
By Caroline Valetkevitch
NEW YORK, July 12 (Reuters) - U.S. stocks fell on Thursday, hit by more warnings in the technology sector, while a rally in Procter & Gamble helped the blue-chip Dow cut its loss.
Shares of consumer products giant Procter & Gamble rose 3.7 percent to $63.70 after a source said activist investor William Ackman appears to be building a stake in the U.S. household products company. Despite the support, the Dow ended lower for a sixth day.
Tech shares remained under pressure, with the S&P technology sector index down 3.5 percent for the month so far. Indian IT heavyweight Infosys Ltd became the latest big tech company to warn of sluggish sales, saying global economic uncertainty was hitting technology spending.
U.S.-listed shares of Infosys slid 11.2 percent to $38.75, after earlier dropping to an all-time low of $38.12.
"I think it is the fear that technology companies are going to miss estimates" this earnings period, said Bruce Zaro, chief technical strategist at Delta Global Asset Management in Boston.
Profit warnings from companies such as Advanced Micro Devices Inc have hurt the sector in recent days. The S&P tech sector index ended Thursday down 1.1 percent.
All three major U.S. stock indexes recovered from their lows of the day, with the S&P 500 bouncing off its 50-day moving average at 1,334 and the Dow briefly trading higher after hitting technical support at 12,500, analysts said.
Merck & Co. shares also bolstered the Dow. Merck's stock rose 4.1 percent to $42.91 after a pivotal trial of Merck's experimental osteoporosis drug odanacatib has shown that it reduces the risk of fracture.
The Dow Jones industrial average shed 31.26 points, or 0.25 percent, to 12,573.27 at the close. The Standard & Poor's 500 Index shed 6.69 points, or 0.50 percent, to 1,334.76. The Nasdaq Composite Index lost 21.79 points, or 0.75 percent, to close at 2,866.19.
The Dow has lost 2.9 percent since its close on July 3.
Overall market sentiment was weak, especially after the lack of any monetary easing by the Bank of Japan on Thursday, and few clues on Wednesday in the minutes from the Federal Reserve's June policy meeting. The lack of policy moves suggested major central banks were still cautious about the need for further easing.
On the earnings front, Bank of America Merrill Lynch Global Research lowered its forecast on the S&P 500's 2012 earnings per share to $102 from $103.50, and for 2013, to $109 from $110.50.
The forecasts were cut "to reflect the impact of lower commodity prices and slower global growth on corporate profits," BofA Merrill Lynch Global Research analysts said in a note.
Hotel operator Marriott International Inc reported a higher quarterly profit after Wednesday's close, b ut cut its fee revenue forecast due to weakness in some international markets. Its stock slid 6.4 percent to $35.58.
Data on the economy showed some promising signs, however. Initial claims for state unemployment benefits in the United States dropped to the lowest in four years.
Other economic data showed U.S. June import prices fell 2.7 percent, the most in more than three years, due to a plunge in the cost of imported oil, further icing inflation pressures.
Volume was a bit lighter than average. About 6.46 billion shares changed hands on the New York Stock Exchange, the Nasdaq and Amex, compared with the year-to-date daily average of 6.85 billion shares. Decliners beat advancers by a ratio of about 19 to 11 on the NYSE and on the Nasdaq, by about 3 to 2.