NYSE 4-Hour Blackout Caused by Technical Glitch


Yesterday’s glitch threw Wall Street into one of the biggest blackouts ever experienced, but the outage was reportedly not a cyber attack

The New York Stock Exchange (NYSE) halted trading on Wednesday at 11.30am EST following an apparent technical glitch.

Service did not resume until almost four hours later at 3.10pm EST.

Internal technical issue

Despite worries of a cyberattack, this has been denied by the NYSE itself and the US Department of Homeland Security. An hour after the glitch began, the NYSE Twitter account said: “The issue we are experiencing is an internal technical issue and is not the result of a cyber breach.

“We chose to suspend trading on NYSE to avoid problems arising from our technical issue. NYSE-listed securities continue to trade unaffected on other market centers.”

NYSE president Thomas Farley said that the outage was because of a configuration problem that was subsequently fixed.

“I can’t say with precision exactly what drove it,” Farley told CNBC. “We found what was wrong and we fixed what was wrong and we have no evidence whatsoever to suspect that it was external.”

Eric Scott Hunsader, a Wall Street expert who works at data firm Nanex, said that clues to the blackout could be seen early Wednesday morning. Hunsader said that at 8.17am EST, the NYSE alerted traders that there was a technical issue that would affect a small number of stocks because of updates to “exchange gateways”. Gateways are the port traders use to place stock orders.


A visual graphic from  Eric Scott Hunsader (@nanexllc) perfectly capturing the trading blackout
A visual graphic from
Eric Scott Hunsader (@nanexllc) perfectly capturing the trading blackout

By 11.20am EST, the NYSE was only operating at 2.6 percent of all trading volume, going down to 2 percent at 11.32am EST. Trading stopped altogether at 11.32 and 57 seconds.

The blackout has been liked that that suffered by Nasdaq in 2013, however, yesterday’s NYSE glitch did not affect trading on other markets.

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