* Sears, Cognizant weigh on Nasdaq
* Chinese internet companies fall ahead of Renren IPO
* Dow flat, S&P off 0.3 pct, Nasdaq down 0.8 pct (Updates to close, changes byline)
By Rodrigo Campos
NEW YORK, May 3 (Reuters) - U.S. stocks fell on Tuesday as investors questioned the sustainability of the rally in light of fresh worries about earnings growth in the coming quarters.
Investors targeted recent top performers, particularly energy shares, which were also hit by a fall in oil prices. The S&P energy index dropped 2.4 percent Tuesday, while oil futures lost more than 2 percent.
The Nasdaq was pressured by losses in Sears Holding Corp after it said it will lose money in the first quarter. Cognizant Technology Solutions Corp was another drag, falling on heavy volume as investors focused on its slowing growth rate.
"There is concern the market is a little overheated and some people are using the opportunity to take some profits," said Peter Jankovskis, co-chief investment officer at OakBrook Investments in Lisle, Illinois.
The S&P 500 fell for a second day after hitting its highest level in nearly three years on Friday at the end of a two-week rally.
"We've had a great earnings season, but above that there's not much on the horizon to further gains in stocks," Jankovskis said.
Chinese Internet stocks fell, with search engine Baidu down 5.2 percent to $139.84 in heavy volume ahead of the initial public offering of Chinese social networking site Renren.
Investor interest in the smaller Facebook competitor was clear last week as Renren raised the expected price range of its IPO 30 percent to $14 from $12 per share.
Online media company SINA Corp dropped 9.5 percent to $122.22.
The Dow Jones industrial average edged up 0.15 points, or 0.00 percent, to 12,807.51. The Standard & Poor's 500 fell 4.60 points, or 0.34 percent, to 1,356.62. The Nasdaq Composite Index lost 22.46 points, or 0.78 percent, to 2,841.62.
Alcoa Inc shares rose 2.6 percent to $17.67 on market talk that Rio Tinto was lining up a bid to buy the U.S. aluminum company. But sources said two banks rumored to be financing the deal were not involved.
Sears's estimate of a quarterly loss late on Monday sent its shares down 9.9 percent to $75.88. Cognizant dropped 5.7 percent to $77.52 on its highest volume since Aug. 4, 2009 as investors focused on its slowing growth rate from hefty levels seen last year.
A Reuters poll showed on Tuesday that U.S. fund managers slightly lowered their exposure to equities in April and raised their allocation in bonds.
About 8.3 billion shares traded on the New York Stock Exchange, NYSE Amex and Nasdaq, above the average of 7.73 billion so far in 2011.
Declining stocks outnumbered advancing ones on the NYSE by a ratio of more than 9 to 5, while on the Nasdaq, more than two stocks fell for every one that rose. (Reporting by Rodrigo Campos; Editing by Kenneth Barry)