Trading has resumed on the New York Stock Exchange after an outage of more than three hours caused by technical problems.
There were no interruptions at the dozens of other U.S. stock exchanges today, including the Nasdaq, so investors were still able to buy and sell NYSE-listed stocks easily.
The NYSE didn't say what the problem was but described it as internal issue and not the result of a breach of its systems.
The market was already lower when the trading halt occurred at about 11:30 a.M. Eastern time as traders worried about China's failure to halt a plunge in its shares and talks remained stuck between Greece and its lenders. NYSE trading resumed at 3:10 p.M. ET.
In the last 20 minutes of trading, the Dow Jones industrial average was down 244 points, or 1.4 percent, at 17,532. The Standard & Poor's 500 index was off 33 points, or 1.6 percent, at 2,048 and the Nasdaq composite was down 87 points, ro 1.7 percent, at 4,910.
The trading halt at the NYSE came on the same day United Continental had to temporarily ground its flights across the country because of computer problems. There was no indication the outages were related.
Tom Caldwell, who runs an investment firm with stakes in several exchanges, says there are some 60 exchanges and trading venues that can take orders when one goes down, so investors shouldn't get rattled.
"It's disruptive, but not wildly disruptive," said Caldwell, chairman of Caldwell Securities. "You have so many competing exchanges."
White House spokesman Josh Earnest said President Obama was briefed by White House counterterrorism and homeland security adviser Lisa Monaco and chief of staff Denis McDonough. Earnest said Obama was also briefed on the United Airlines glitch that temporarily grounded its flights.
"There is no indication at this point either that there is malicious activity involved or that it was related to any of the other high profile technology issues that have cropped up today."
FBI Director James Comey, testifying before the Senate Intelligence committee, said the agency has been in contact with the NYSE, United Continental, and the Wall Street Journal, whose web site briefly went down today as well.
"We do not see any indication of a cyber breach or a cyber attack," Comey said. "I think the Wall Street Journal piece is connected to people flooding their web site in response to the New York Stock Exchange to find out what's going on. In my business, you don't love coincidences, but it does appear that there is NOT a cyber intrusion involved.
