Slightly better-than-expected jobs and services data buoyed U.S. stocks on Wednesday, with Priceline.com's upbeat outlook lending support.

Priceline.com Inc
soared 22 percent to $281.33 after several brokers raised price estimates for the online travel agency's stock, based on its stronger-than-expected quarterly results.

Priceline was the top performer in both the S&P 500 <.SPX> and the Nasdaq 100 <.NDX>.

Data from the Institute for Supply Management showed the services sector grew at a faster pace than expected in July. In a separate report, payroll-processing company ADP said private employers added more jobs in July than forecast.

Still, the picture of the economy was listless. Investors remained cautious before the U.S. government's key monthly jobs report expected Friday.

ADP certainly gave a little glimmer of hope the jobs number on Friday might be more positive than anticipated, said Kim Caughey, senior equity research analyst at Fort Pitt Capital Group in Pittsburgh.

But she said the high unemployment rate keeps consumers jittery and retailers' margins are probably being hit as they try to drive sales.

The high proportion of the economy that is consumer oriented gives investors pause, she said.

Friday's government report on jobs is expected to show a drop of 65,000 in July as Census jobs evaporated.

The Dow Jones industrial average <.DJI> added 41.86 points, or 0.39 percent, to 10,678.24. The Standard & Poor's 500 <.SPX> rose 5.42 points, or 0.48 percent, to 1,125.88. The Nasdaq Composite <.IXIC> gained 15.51 points, or 0.68 percent, to 2,299.03.

With 80 percent of the S&P 500 companies having reported quarterly results, estimated and reported earnings growth stands at 37.3 percent for the previous quarter, up from an estimate of 27.4 percent a month ago, according to Thomson Reuters Proprietary Research.

The Nasdaq also got a lift from Dendreon Corp , up 15.1 percent at $38.90 on details of the launch of the company's new prostate cancer vaccine and news that it was piling up favorable reimbursement notices from health plans.

Barnes & Noble shot up 20.6 percent to $15.48 after the No. 1 U.S. bookstore chain put itself up for sale as business suffers in the high-stakes battle for a leading role in the digital books market.

Shares of industry giant Amazon.com , which sells the Kindle electronic reader and e-books, rose 4.4 percent to $127.82.

Goldman Sachs Group Inc added 1.9 percent to $156.11 as the Wall Street firm plans to spin off its proprietary trading business as early as this month to comply with the U.S. financial reform package signed into law last month, according to a CNBC report.

Blue-chip Microsoft Corp weighed on the downside, losing 2.3 percent to $25.57 after Global Equities Research downgraded the stock to equal weight from overweight.