Confirmation that Halliburton is in talks to buy rival Baker Hughes lit up oil service sector shares Friday, but overall markets were flat in early trade.
Investors were cautious after the Dow Jones Industrial Average set a fresh record Thursday, its fifth in six sessions, and the S&P 500 barely missed a new mark.
About 45 minutes into trade, the Dow Jones Industrial Average, which eked out a new record Thursday, was up 10.85 points (0.06 percent) to 17,663.64.
The broad-market S&P 500 gained 2.54 points (0.12 percent) at 2,041.87, while the tech-rich Nasdaq Composite fell 3.44 (0.07 percent) at 4,683.58.
The possibility of the huge oil industry merger sent Baker Hughes up 1.1 percent, after Thursday's 15 percent-plus gain.
The two companies confirmed reports that they were in talks, though no details on pricing or other issues were given.
Analysts expect Halliburton to pay a premium over what was Baker Hughes' $22 billion market valuation before the news of the talks leaked out Thursday.
At Friday morning's price of $59.38, the company was worth $25.7 billion.
Halliburton shares meanwhile gained 2.6 percent and industry powerhouse Schlumberger rose 2.0 percent on the news, while shares of smaller service companies, especially fracking specialists, also surged.
Shares of car rental agency Hertz sank 5.5 percent after it confirmed plans to restate earnings for 2012 and 2013 amid a probe into the company's accounting.
Bond prices were mixed. The yield on the 10-year US Treasury rose to 2.36 percent from 2.35 percent Thursday, while the 30-year fell to 3.07 percent from 3.08 percent.
Bond prices and yields move inversely.