The S&P health sector tumbled 1.8 percent, the most among the 11 major sectors. Health insurer UnitedHealth's 3.2 percent drop was the most on the Dow, while Express Scripts' 6.2 percent decline weighed the most on the Nasdaq and S&P. The Fed's ongoing two-day meeting will be watched for comments that could raise the likelihood of rates being hiked four times this year, instead of three, especially as inflation readings have firmed in recent readings.
"Investors are getting a bit worried about inflation which has led some people to believe that the Fed might be more aggressive when it comes to raising rates," said Robert Pavlik, chief investment strategist at SlateStone Wealth. At 12:33 pm ET (1733 GMT), the Dow Jones Industrial Average was down 333.27 points, or 1.26 percent, at 26,106.21. The index fell as much as 352 points, its steepest intraday point drop since May 17.
The S&P 500 was down 27.82 points, or 0.97 percent, at 2,825.71 and the Nasdaq Composite was down 60.17 points, or 0.81 percent, at 7,406.33. The CBOE Volatility Index, the most widely followed gauge for investors' "fears", rose to as much as 15.42, its highest level since August.