Stocks tumble in sell-off; Dow closes down 264 points

The U.S. stock market closed sharply down Thursday following the largest sell-off in two months, with the Dow Jones industrial average dipping 264 points.

Investors pointed to a collection of factors for the slide on Wall Street, including problems at Apple, monetary policy and long-simmering geopolitical concerns.

The Dow sank 1.5% to 16,945.8 points, dipping below 17,000 for the first time in more than a week. The Standard & Poor’s 500 index dipped 1.6%, falling 32 points to 1,966.

The Nasdaq composite, which is heavily stacked with technology stocks, took a heavy hit with a 1.9% decline, or 88 points, to 4,467.

Wall Street analysts said several forces were likely at play.

Iraq’s prime minister said Thursday that his country’s government found evidence of terrorist plots targeted at subway systems in the U.S. and Paris.

The Russian parliament is considering a law that could allow the nation’s courts to seize foreign assets on Russian territory -- considered a reaction to sanctions imposed by Western governments over the conflict in the Ukraine.

Apple’s stock slid nearly 4%, or $3.88, to $97.87 a share as investors reacted to complaints from iPhone users that the company’s new software update, which it rescinded late Wednesday, was buggy.