New York: The New York Stock Exchange suspended trading in all stocks Wednesday morning due to an apparent technical problem.
The NYSE halted trade just after 1530 GMT (11:30 EST), saying in a notice on its website that "additional information will follow as soon as possible."
CNBC quoted the exchange as citing "technical issues" for the problem.
NYSE said in a subsequent notice that it cancelled all open orders.
Major stocks listed on the NYSE continued to trade on the Nasdaq and BATS, the third largest US exchange.
The Nasdaq suffered the last major outage on a major US exchange, going down for three hours in August 2013 due to technical problems.
The outage also came on the same day as United Airlines grounded planes at US airports for an hour due to a computer glitch. The website for the Wall Street Journal newspaper was also suffering intermittent glitches.
At 1615 GMT, the Dow Jones Industrial Average was at 17,562.42, down 214.49 points (1.21 percent).
The broad-based S&P 500 fell 27.56 (1.32 percent) to 2,053.78, while the tech-rich Nasdaq Composite Index lost 73.49 (1.47 percent) to 4,923.97.