NEW YORK (CNNMoney.com) - Stocks struggled early Monday as a jump in shares of Pfizer after a patent ruling weren't enough to ignite a broader round of buying.

The Dow Jones industrial average (down 6.08 to 10,875.59, Charts) and the S&P 500 (up 2.61 to 1,269.93, Charts) index barely edged higher in the first half hour of trading.

The Nasdaq composite (down 4.71 to 2,247.77, Charts) slipped about 0.3 percent.

The market has been skittish in recent weeks after November's big rally, leaving many investors wondering whether the traditional year-end rally has already happened.

Oil prices edged higher in early trading, after falling below $59 a barrel Friday.

The January light crude futures contract gained 32 cents to $58.06 a barrel in electronic trading, while the February contract for Brent crude added 39 cents to $57.52.

Bond prices fell, with yields on the 10-year treasury rising to 4.46 percent from 4.44 percent late Friday. Bond prices and yields move in opposite directions.

The dollar gained against the yen but was little changed against the euro.

In global markets, Asia stocks ended higher while European shares were mixed at midday.

In individual issues, drugmaker Pfizer (up $2.37 to $24.95, Research) surged over 10 percent following news Friday that the company won a court victory upholding the validity of two key U.S. patents on Lipitor, its cholesterol-lowering drug that is the world's biggest selling prescription drug.

The ruling is likely to delay plans by an Indian drugmaker to introduce a generic version of the medicine.

Time Warner (up $0.13 to $18.13, Research) is reportedly close to a deal to sell a 5 percent stake in America Online, its online unit, to search engine Google (Research) for $1 billion in cash, along with closer ties between the two in ad sales.

The deal, which was first reported in the online edition of the Wall Street Journal late in the trading day Friday, helped lift shares of Time Warner and dented Microsoft shares. CNN/Money is a unit of Time Warner.

FPL (up $0.56 to $43.51, Research) announced early Monday that it had reached an agreement to buy Constellation Energy (down $1.63 to $59.99, Research) in an $11 billion stock deal that the companies say will create the nation's No. 2 electric utility.

The deal, which was widely reported last week, pays little premium from Friday's closing price but the companies' statement says it pays a 15 percent premium on the 20-day average price ending Dec. 13.