A technical glitch forced the New York Stock Exchange to suspend trading for more than three hours on Wednesday in the biggest outage to strike a U.S. 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 (ICE.N), said the halt, which occurred shortly after 11:30 a.m. EDT and lasted until 3:10 p.m., was 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.
Traders awaited the reopening anxiously because much of the business on the NYSE happens when portfolio managers put in orders designed to occur at the exact market close to ensure end-of-day pricing.
The NYSE accounts for more than 60 percent of S&P 500 .SPX volume at the close of the market, according to Credit Suisse analyst Ana Avramovic. Most of this is at the "market-on-close," when those orders are processed for funds and institutions.
"If you don't have all the orders on that marketplace on the close, the pricing on the close would be definitely not accurate," said Empire Executions Inc President Peter Costa, who trades on the NYSE floor.
