Wall Street advanced for a third straight day on Friday, giving the S&P its best weekly performance since early February, but volume remained light as global uncertainty persisted.

The three major stock indexes posted weekly gains after two straight weeks of declines brought on by the Japan earthquake, turmoil in the Arab world and a resurfacing of European debt problems.

Helped by a rise in tech shares after an upbeat outlook from Oracle Corp, the S&P notched its best week since early December. But low volume, and the market's uncanny ability to withstand bad news, spurred questions about the rally's strength.

Overall, I keep looking at the pluses and minuses and this week has been spectacular with respect to everybody ignoring the minuses, said Kim Caughey Forrest, senior equity research analyst at Fort Pitt Capital Group in Pittsburgh.

The CBOE Volatility Index <.VIX> posted its second-worst seven-day run as investors shed anxieties about the global tumult.

Friday's trading volume of 6.56 billion shares on the New York Stock Exchange, NYSE Amex and Nasdaq, was weak, with Friday's session the second-lowest of the year, pointing to a lack of conviction. Daily average volume is 8.04 billion.

Oracle's stock climbed 1.6 percent to $32.64 and was the Nasdaq's most actively traded name a day after forecasting a rise in new software sales for its current fiscal quarter. The outlook fueled hopes that a global resurgence in tech spending remains intact, prompting at least 12 brokerages to raise their price targets on the stock.

The S&P technology index <.GSPT> rose edged up 0.2 percent on Friday, and is up 3.3 percent so far this quarter.

In a further boost to techs, Accenture rose 4.5 percent to $54.29 after the technology outsourcing and consulting company raised its outlook.

The Dow Jones industrial average <.DJI> gained 50.03 points, or 0.41 percent, to 12,220.59. The Standard & Poor's 500 Index <.SPX> rose 4.14 points, or 0.32 percent, to 1,313.80. The Nasdaq Composite Index <.IXIC> added 6.64 points, or 0.24 percent, to 2,743.06.

For the week, the Dow gained 3.1 percent, the S&P climbed 2.7 percent and the Nasdaq advanced 3.8 percent.

On the downside in tech shares, BlackBerry maker Research In Motion Ltd said earnings would slip as it spends heavily to launch its PlayBook tablet. The company's U.S.-listed shares sank 11.2 percent to $56.89.

On the economic data front, the Commerce Department reported that the U.S. economy grew more quickly than previously estimated in the fourth quarter of 2010 as businesses restocked shelves to meet rising demand.

U.S. consumer sentiment in March fell to its lowest level in more than a year as gasoline and food prices rose, according to the latest consumer survey from Thomson Reuters and the University of Michigan.

Advancing stocks outnumbered declining ones on the NYSE by 1,969 to 1,015, while on the Nasdaq, advancers beat decliners 1,515 to 1,092.

(Reporting by Chuck Mikolajczak; Editing by Jan Paschal)

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