A BUSTED BOARD

NYSE 4- hour fail was snafu, not cyberattack

The stock exchange stopped, but the stock market worked.

Trading on the New York Stock Exchange ground to a halt for almost four hours Wednesday because of a computer glitch — the longest shutdown for the 223yearold exchange since Superstorm Sandy in 2012.

But with 11 exchanges now handling shares traded on the NYSE, the investing public barely felt a ripple.

“The US capital markets system is flexible enough to deal with these issues,” said Michael Wong, an analyst at Morningstar.

“It wasn’t like frommy seat that all of a sudden you had to call the trading desk to get something executed manually,” one broker told The Post. “Everything systems wise is flawless.”

NYSE President Thomas Farley, while unable to provide much concrete answers, suggested during a TV interview that a system upgrade may be the cause for the outage.

There were spasms of inactivity in premarket trading thatwas believed to have been fixed by the opening bell.

By 11: 32 a. m. that optimism was tested when trading halted — adding to market turbulence as stocks reacted worldwide to the Federal Reserve’s June meeting minutes and to news that United Continental was grounding flights because of a computer glitch.

When the homepage of the Wall Street Journal also went down, nerves frayed further as some market watchers feared a coordinated cyberattack.

But that fear was quickly set aside as the FBI and Homeland Security — and NYSE officials — said the three glitches were unrelated and that no cyberattack had occurred.

“Any time you have machinery that is also controlled by man, then problems are bound to happen,” Sam Stovall, US equity strategist for S& P Capital IQ, told The Post.

“It adds to the overall level of uncertainty,” he added.

Trading resumed at 3: 10 p. m. until the closing bell.

While NYSE, which is operated by Intercontinental Exchange, or ICE, is the symbol of US capitalism, traders were still able to buy and sell on 10 other exchanges, including the Nasdaq and BATS, as well as “dark pools,” or exchanges run by Wall Street banks, where 40 percent of stock trading occurs.

The technological nature had traders comparing Wednesday’s debacle to the 2010 “Flash Crash” — when the Dow industrials swung 1,000 points in five minutes— and to Nasdaq’s botched initial public offering for Facebook in 2012.

“The issue we are experiencing is an internal technical issue andi s not the result of a cyber breach,” the NYSE announced over Twitter. “We chose to suspend trading on NYSE to avoid problems arising fromour technical issue.”

Mary Jo White’s Securities and Exchange Commission said it was “closely monitoring the situation” with the exchange, she said in a statement.

At the end of the day, the decentralized nature of stock trading was the hero.

The Dow industrials ended the day down 261.49 points, or 1.5 percent, to 17,515.42, while ICE fell 2.4 percent, to $ 221.86.