Apple's iPhone troubles sank stocks. The technology giant's shares dropped almost 4 percent Thursday after it had to yank an update to its operating system amid complaints it was blocking users' cellphone service. Apple's fall dragged down the tech-heavy Nasdaq, which in turn pulled down shares on the Dow and the S&P 500. The Dow dropped 264.26 points to 16945.80, the Nasdaq fell 88.47 to 4466.75 and the S&P 500 slid 32.31 to 1965.99.
It was the worst session for major benchmark indexes since July 31. The CBOE Volatility Index, a measure of investor uncertainty, jumped 21 percent to 16.05; the price of gold turned higher and Treasuries rallied. Investors were also unnerved by a proposal in Russia that would let it courts seize foreign assets. Reuters reported the draft law, submitted to Russia's parliament on Wednesday by a pro-Kremlin deputy, would also allow state compensation for those whose assets were taken in foreign jurisdictions.
-- NBC News staff and CNBC