A swoon in technology stocks on Thursday left the market with its worst drop since July. Apple sank nearly 4 percent after the company pulled a software update for the iPhone after users complained that they weren't able to make calls.
The Dow Jones industrial average lost 264.26 points, or 1.5 percent, to close at 16,945.80.
The S&P 500 index lost 32.31 points, or 1.6 percent, to close at 1,965.99.
The Nasdaq composite lost 88.47 points, or 1.9 percent, to 4,466.75.
For the week:
The Dow is down 333.94 points, or 1.9 percent.
The S&P 500 has fallen 44.41 points, or 2.2 percent.
The Nasdaq composite is down 113.04 points, or 2.5 percent.
For the year:
The Dow is up 369.14 points, or 2.2 percent.
The S&P 500 index is up 117.63 points, or 6.4 percent.
The Nasdaq is up 290.16 points, or 7 percent.