By Caroline Valetkevitch
NEW YORK (Reuters) - U.S. stocks ended modestly higher on Friday, led by technology shares, though a downbeat second-quarter forecast from DuPont Co kept a lid on gains.
The S&P 500 technology index rose 0.6 percent, bolstered by Apple Inc, up 1.2 percent at $91.98, in another session this week where the Nasdaq outperformed the other two major indexes.
Both the Dow and the S&P 500 ended with slight losses for the week, while the Nasdaq scored a gain.
Trading volume, which has been low in recent weeks, surged to at least 8.8 billion shares on U.S. exchanges, according to BATS Global Markets. The spike in volume at Friday's close was the result of Russell Investments' final reconstitution of its indexes, which affected more than $5 trillion in assets.
DuPont shares lost 3.3 percent to $65.44 and ranked among the biggest drags on both the Dow and the S&P 500. The losses came a day after the company cut its operating profit forecast for the second quarter and the full year, citing slower sales at its agriculture and performance chemicals units.
It was the latest company to warn on the quarter, with the ratio of negative to positive outlooks now at 4.2 to 1, above the long-term average of 2.6 to 1, Thomson Reuters data showed.
The earnings period will start in about two weeks, giving investors the next set of clues on whether the economy and profits are picking up.
"Prices have finally achieved a certain valuation level that has become increasingly uncomfortable for market participants in the absence of further decisive evidence that the economy is on the right track," said Mark Luschini, chief investment strategist at Janney Montgomery Scott in Philadelphia.
The forward price-to-earnings ratio on the S&P 500 is 15.9, the highest since 2008, Thomson Reuters data showed.
The Dow Jones industrial average rose 5.71 points or 0.03 percent, to end at 16,851.84. The S&P 500 gained 3.74 points or 0.19 percent, to 1,960.96. The Nasdaq Composite added 18.88 points or 0.43 percent, to 4,397.93.
For the week, the Dow slipped 0.6 percent and the S&P 500 declined 0.1 percent, while the Nasdaq gained 0.7 percent.
Despite the market's recent malaise, Wall Street's 2014 rally was expected to extend into the second half of the year.
A Reuters poll on Thursday showed the S&P 500 is expected to hit 2,000 before the end of 2014.
Among the day's positive signs, U.S. consumer sentiment rose more than expected, according to the Thomson Reuters/University of Michigan's final June reading, though that followed weak readings on consumer spending and first-quarter economic activity earlier this week.
Shares of Nike Inc rose 1.1 percent to $77.68 a day after the sports apparel and shoe company reported fourth-quarter earnings that beat expectations.
(Editing by Bernadette Baum, Nick Zieminski and Jan Paschal)