US stocks were little changed on Friday as a rise in oil prices triggered by Middle East tensions boosted energy stocks but weighed on the broad market. Gains on the Nasdaq market were stemmed by shares of Amgen Inc after the world's largest biotechnology company cancelled a clinical trial involving a colon cancer drug.
The Dow industrials clung to positive territory, buoyed by a 4 percent rise in General Motors Corp shares amid indications the automaker was unlikely to buy rival Chrysler.
Trading volume was below average, and stocks flipped from positive to negative several times throughout the session. The Dow Jones industrial average was up 9.94 points, or 0.08 percent, at 12,471.08. The Standard & Poor's 500 Index was up 0.24 point, or 0.02 percent, at 1,434.78. The Nasdaq Composite Index was up 2.62 points, or 0.11 percent, at 2,454.36.
Amgen shares were down 3.9 percent to $58.10 on the Nasdaq. Shares of ImClone, which makes a competing drug, rose 12.5 percent to $38.14 on the New York Stock Exchange.
GM shares jumped more than 4.2 percent to $31.59 as investors speculated that the automaker would be less likely to buy Chrysler. Two private equity firms and Canadian auto parts supplier Magna International Inc have emerged as the leading candidates for buyers.
The rise in oil prices lifted oil company stocks. Shares of Exxon Mobil Corp, another Dow constituent, rose 0.7 percent to $74.94 on the NYSE. Shares of Chevron Corp were up 1.2 percent to $73.77 on the NYSE.
Stocks briefly jumped on a report showing an unexpected rise in existing-home sales last month but pared those gains after investors noted that prices have stagnated and the inventory of unsold homes had increased.