Stocks are plunging as traders dump risky assets and park their money in investments seen as relatively safe, such as U.S. government bonds.
The Dow Jones industrial average dropped 440 points, or 2.7 percent, to 15,873 as of 1:25 p.m. Eastern time Wednesday.
The Standard & Poor's 500 fell 53 points, or 2.9 percent, to 1,823. The Nasdaq composite fell 104 points, or 2.5 percent, 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 percent from its record high reached Sept. 18. That's close to the 10 percent drop that market watchers refer to as a "correction."
Bond prices soared as investors shifted money into safe-haven investments.