The Dow Jones industrial average dropped 440 points, or 2.7 per cent, to 15,873 as of 1:25 p.m. Eastern time Wednesday.
The Standard & Poor's 500 fell 53 points, or 2.9 per cent, to 1,823. The Nasdaq composite fell 104 points, or 2.5 per cent, to 4,122.
The Dow is on pace for its worst drop since August 2011.
All three indexes are now negative for the year. The S&P is down 9 per cent from its record high reached Sept. 18. That's close to the 10 per cent drop that market watchers refer to as a "correction."
Bond prices soared as investors shifted money into safe-haven investments.