New York - A second straight selloff of popular technology shares dragged US stocks lower on Monday, as tensions with Russia over Ukraine kept investors on edge.
The Dow Jones Industrial Average finished down 26.08 points at 16 276.69.
The broad-based S&P 500 lost 9.08 points at 1 857.44, while the tech-rich Nasdaq Composite fell 50.40 points to 4 226.38.
The action kept up a bearish turn that took root on Friday, when the Nasdaq gave up 1%.
On Monday the Nasdaq at one point was down more than 2%, before halving that loss.
Besides the already heady valuations, ongoing worries that Russia might launch an additional land-grab in Ukraine after annexing Crimea lay behind the selling.
In addition, a turn lower for HSBC's purchasing manager index for China suggested weaker growth than expected in that key economy.
Some of the most popular Nasdaq counters took sharp falls: LinkedIn (-4.4%), Priceline (-3.32%), Facebook (-4.7%), Netflix (-6.7%), Tesla (-3.8%) and Twitter (-4.2%).
"People are starting to be a bit nervous about the valuations of some of the high-flyers," said Peter Coleman of ConvergEx group.
Online music streamer Pandora Media took a 7.7% fall after Apple was reported in talks to stream its services via Comcast's network and also exploring an iTunes app for Android devices that could compete with Pandora.
Apple gained 1.2% and Comcast 0.6%.
Trade was heavy in biotech stocks: Gilead Sciences overcame early losses to add 0.1%, while Biogen Idec slid 1.8% on top of its 10% loss between Wednesday and Friday last week.
Procter and Gamble led the Dow gainers up 1.8%, while Pfizer was the biggest loser, its shares down 2.1% after the release of disappointing results of clinical tests on its Tofacitinib psoriasis treatment.
Bond prices were higher. The yield on the 10-year US Treasury fell to 2.73% from 2.74% late on Friday, while the 30-year dropped to 3.57% from 3.61%. Bond prices and yields move inversely.