An encouraging October jobs report gave shares an early bump Friday but the gains were all quickly lost and the main indices ended in the red, as caution grew ahead of next Tuesday's election.
Although the jobless rate ticked up to 7.9 percent, the fact that the economy could pump out 171,000 net new jobs last month was seen as good for President Barack Obama and a negative for challenger Mitt Romney, the Wall Street favorite.
The markets also were pulled down by Apple's 3.3 percent fall, amid a lukewarm reception for its new iPad mini.
The Dow Jones Industrial Average finished down 139.46 points (1.05 percent) at 13,093.16.
The broad-based S&P 500 fell 13.39 (0.94 percent) to 1,414.20, and the Nasdaq Composite lost 37.93 (1.26 percent) at 2,982.13.
The jobs data was a good sign for the economy, analysts said.
"The October payroll survey showed a brighter picture of the labor market, both in faster headline job creation and in upward revisions to previous months," said Nigel Gault of IHS Global Insight.
In stocks, insurer AIG fell 7.2 percent despite its third-quarter earnings handily beating estimates as the company swung into the black, earning $1.9 billion.
But worries about the costs to the economy from Hurricane Sandy, which could lead to insured losses industry-wide of $20 billion according to estimates, kept a cloud over the shares.
"We are seeing continued momentum, and we're building for the future by creating a more streamlined, efficient, and nimble company," AIG chief executive Robert Benmosche said in a statement.
Other insurers took a hit: Hartford Financial fell 3.0 percent, and Travelers 0.9 percent.
Power companies hit by extended outages in the storm sank: Exelon fell 2.4 percent, Con Ed lost 0.9 percent and New Jersey's PSEG was down 0.2 percent.
Mining companies weakened amid a sharp fall in gold prices: Freeport McMoRan lost 3.1 percent and Newmont Mining lost 8.4 percent.
Chevron, the oil giant, dropped 2.8 percent after reporting a fall in quarterly profit due to lower crude output.
Among gainers, Starbucks added 9.1 percent after turning in strong earnings and boosting its dividend.
Bond prices gained slightly. The 10-year US Treasury yield fell to 1.71 percent from 1.72 percent late Thursday, and the 30-year held at 2.90 percent.