NYSE shut down for nearly four hours by technical glitch

An NYSE official gestures after the resumption of trading following a several hour long stoppage on the floor of the New York Stock Exchange, July 8, 2015. [Photo/Agencies]

NEW YORK - The New York Stock Exchange was forced to suspend trading for several hours on Wednesday in the biggest outage to hit a US financial market in nearly two years, unnerving investors already rattled by the meltdown in Chinese stocks and the Greek debt crisis.

The exchange, a unit of Intercontinental Exchange Inc , reopened at 3:10 pm EDT (1910 GMT) after being halted shortly after 11:30 am EDT. NYSE said the outage was due to an internal technical issue and not the result of a cyberattack. Other exchanges were trading normally.

"It's not a good day, and I don't feel good for our customers who are having to deal with the fallout," NYSE President Thomas Farley told CNBC during the halt.

NYSE, which traces its roots back to an agreement under a Buttonwood tree on Wall Street in 1792, handled 6.12 percent of US stock volume for the day, with much of that coming after the exchange reopened, according to statistics from BATS Global Markets. That compares to an average of about 13.4 percent last month.

Traders had awaited the reopening anxiously because much of the NYSE's business happens when portfolio managers put in orders designed to occur at the exact market close to ensure end-of-day pricing.

However, many traders said that it did not matter that the NYSE was down. That's because there are 11 US stock exchanges, including those run by Nasdaq OMX Group and BATS, along with more than 40 private stock-trading venues, so the trading of NYSE-listed stocks was uninterrupted.

"This is one of the rare cases where the fragmented markets we live in actually serve a purpose," said Dave Nadig, director of exchange-traded funds at FactSet Research Systems. "If this happened at (the London Stock Exchange), you would just be sitting staring at a blank screen."