The Dow Jones industrial average closed down 317 points Thursday after a wild plunge in the final half-hour of trading.
At the close on Wall Street, the Dow was down 317.1 points, nearly 2 percent, at 16,563.3. The Standard & Poor's 500 index closed down 39.4 points, 2 percent, at 1,930.7. The Nasdaq composite ended the day with a loss of 93.1 points, nearly 2.1 percent, at 4,369.8.
The U.S. markets joined a global sell-off, sending the S&P 500 toward its first monthly drop since January, as shares of companies from Exxon Mobil Corp. to Micron Technology Inc. tumbled with weaker corporate results.
"The Fed is stepping out of the way and the market's valuation is high enough that people are quick to take profit," Wayne Wilbanks, who oversees $2.5 billion as chief investment officer at Wilbanks, Smith & Thomas Asset Management LLC in Norfolk, Virginia, said in a phone interview. "You are going to get more days like today, where investors are more trigger-happy, quicker to liquidate. Everybody knows a correction is coming and it will come."
The S&P 500, which is up 4.6 percent this year and reached a record on July 24, has gone without a 10 percent correction since 2011. It trades at 17.6 times the reported earnings of its companies, near the highest level since 2010.
The S&P 500 ended its longest stretch of calm since 1995 this month. Including Thursday, the index has posted gains or losses of more than 1 percent three times in the past two weeks, compared with none during the 62 days through July 16, data compiled by Bloomberg show.
Reports from Bloomberg News and The Associated Press were used in this story.