* Quarter-end window dressing boosts market * Earnings optimism stays; Oracle to report after the bell * Dow up 0.6 pct, S&P up 0.7 pct, Nasdaq up 1.1 pct
* For up-to-the-minute market news see [STXNEWS/US] (Updates to early afternoon)
By Caroline Valetkevitch
NEW YORK, March 24 (Reuters) - U.S. stocks advanced on Thursday, helped by optimism about earnings and investors buying the quarter's high performers, while the S&P 500's push above a key level could signal further gains.
The S&P 500 broke above its 50-day moving average at 1,305, and analysts said the market may have gotten past the worst of its recent pullback.
"What I saw yesterday and today is a stabilization of the market," said Bruce Zaro, chief technical strategist at Delta Global Asset Management in Boston.
"There have been a few good earnings reports that have given investors a bit more confidence that earnings are likely to hold ... so the story will continue that the rally has been built on strong earnings momentum," he said.
The Dow has a good chance of making a new 12-month high in the next six weeks, Zaro said. The current high is 12,391.
The S&P 500 is up 24 percent since the start of September but briefly dipped into negative territory for the year recently amid worries about high oil prices and the disaster in Japan.
The S&P 500 consumer discretionary index was up 1.3 percent after electronics retailer Best Buy reported better-than-expected earnings on strong smartphone sales.
Best Buy's stock, however, was down 4 percent at $30.58, reversing earlier gains that took it as high as $32.98. The stock also touched a fresh 52-week low at $30.24.
Oracle, due to report after the close, gained 1.4 percent to $31.83 and helped lift the Nasdaq, which was up more than 1 percent.
The Dow Jones industrial average was up 74.47 points, or 0.62 percent, at 12,160.49. The Standard & Poor's 500 Index was up 9.10 points, or 0.70 percent, at 1,306.64. The Nasdaq Composite Index was up 29.86 points, or 1.11 percent, at 2,728.16.
It was a second day of gains for the market, with the S&P 500 up 1.9 percent so far for the week.
"I don't think the pullbacks from here will have much substance or bite to them," said Steve Goldman, market strategist at Weeden & Co. in Greenwich, Connecticut. "The path of least resistance still remains higher."
With the market near the end of the quarter, portfolio managers will buy equities as they execute window dressing, and hedge funds will cover short positions that are under pressure.
The S&P energy index is among leading sectors for the quarter, with gains so far of 13.5 percent. But the index was flat on Thursday.
The S&P technology index, up 2.7 percent so far for the quarter, was up 1.2 percent on Thursday.
A semiconductor index was up 2.2 percent.
Red Hat Inc surged 17.5 percent to $46.97 after a brokerage upgraded the stock. The company's earnings topped estimates late Wednesday.
Earnings growth is expected to help the market overcome worries about unrest in the Middle East and North Africa and Japan's crisis this year.
The S&P 500 was forecast to end the year 11 percent higher, according to a Reuters poll released on Thursday. (Reporting by Caroline Valetkevitch; Editing by Jan Paschal)