U.S. stocks opened higher on Wednesday, led by energy and financial companies due to higher crude oil prices and optimism about technology spending was up after reassuring comments from Cisco Systems Inc.

The services sector data, which came in above a record low result in January, overshadowed a report which said the private-sector employment dropped unexpectedly in February.

Fannie Mae, the largest U.S. source of mortgage financing, climbed after Morgan Stanley said earnings may improve next year, pushing financial shares up. Ambac Financial Group Inc., the second-biggest bond guarantor, rallied for a second day and sparked a rebound in financial shares from a four-year low.

The Standard & Poor's 500 Index added 6.48 points, or 0.5 percent, to 1,333.23 at 10:00 a.m. in New York. The Dow Jones Industrial Average advanced 44.12, or 0.4 percent, to 12,257.92. The technology heavy Nasdaq Composite Index increased 15.05, or 0.7 percent, to 2,275.33. Three stocks advanced for every one that fell on the New York Stock Exchange.

Ambac gained 54 cents, or 5 percent, to $11.26 after climbing 7.9 percent yesterday. Fannie Mae rose 39 cents to $26.34.

Schlumberger, the largest oilfield services company, climbed $1.58 to $86.13. Crude oil for April delivery increased as much as 1.4 percent to $100.87 a barrel in New York.

The jobs data from ADP Employer Services comes two days before the government's key monthly employment report. Other data showed new orders for U.S. factories fell in January, in line with expectations.