--- description: The exchange went down for nearly 4 hours as a result of software testing. title: NYSE Explains Why It Went Down Wednesday image: https://static.time.com/v3/assets/bltea6093859af6183b/blt7c8cd369c28fee8c/69885a478e06010ed0461525/gettyimages-479944324.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  * [Business](/section/business/) ## Business Update your preferences in [Account Settings](/account/preferences/) Close * [Tech](/tag/time-section-tech/) ## Tech Update your preferences in [Account Settings](/account/preferences/) Close # NYSE Explains Why It Went Down Wednesday by [Laura Lorenzetti / Fortune](/author/fortune/) ## Laura Lorenzetti / Fortune Update your preferences in [Account Settings](/account/preferences/) Close Jul 9, 2015 5:19 PM CUT  Traders work on the floor of the New York Stock Exchange (NYSE) at the close of the day after trading was resumed an over three hour closure of the market due to a "technical glitch" on July 8, 2015 in New York City. Traders work on the floor of the New York Stock Exchange (NYSE) at the close of the day after trading was resumed an over three hour closure of the market due to a "technical glitch" on July 8, 2015 in New York City.Spencer Platt—2015 Getty Images by [Laura Lorenzetti / Fortune](/author/fortune/) ## Laura Lorenzetti / Fortune Update your preferences in [Account Settings](/account/preferences/) Close Jul 9, 2015 5:19 PM CUT The New York Stock Exchange crashed Wednesday at 11:32 a.m. ET and remained down for exactly [3 hours and 38 minutes](http://fortune.com/2015/07/08/nyse-back-online/ "undefined"). It caught many traders off guard and raised concerns of what was happening behind the scenes that might have caused the “technical glitch,” the company said it encountered. The NYSE now has [a detailed explanation](https://www.nyse.com/market-status/history "undefined") and it all comes down to the rollout of a new software release. (The one that was referenced in [_Fortune_‘s interview](http://fortune.com/2015/07/08/nyse-halt/ "undefined") with trading systems expert Scott Hunsader yesterday.) The exchange was prepping for a July 11 industry test that’s on the horizon, which will test the platform’s SIP timestamp requirement. The software update was rolled out to one trading unit–the standard practice. But, as investors started logging on Wednesday morning, a series of communications issues popped up between customer gateways (what investors use to connect to the NYSE) and the trading unit using the new software. It turns out that those gateways were not loaded with the proper information needed to work in tandem with the release, so the NYSE updated the gateways with the correct version of software and opened for trading as usual at 9:30 a.m. However, the update didn’t go as planned and the communication issues proliferated, causing the exchange to [send out a message](http://fortune.com/2015/07/08/nyse-halt/ "undefined") that a technical issue was being investigated at 11:09 a.m. ET before suspending all trading at 11:32 a.m. ET. The NYSE then went about canceling all open orders as well as working with customers to reconcile orders and trades, all while restarting all customer gateways and implementing a complete system restart after consulting with regulators and industry peers. After that, the NYSE got everything [back up and running](http://fortune.com/2015/07/08/nyse-back-online/ "undefined") by 3:10 p.m. ET. ### Market Woes: Remembering the ‘Flash Crash’ of 1962  Caption from June 8, 1962, issue of LIFE. "What went wrong in the wild stock market and what it means for the U.S." John Dominis—Time & Life Pictures/Getty Images  Not originally published in LIFE. The NYSE during the 1962 "flash crash." Yale Joel—Time & Life Pictures/Getty Images  Not originally published in LIFE. Tense scene at a brokerage office during the 1962 stock market "flash crash." John Dominis—Time & Life Pictures/Getty Images  Caption to very similar picture in June 8, 1962, issue of LIFE. "Floor of New York Stock Exchange boils with frenzy of an overheated pot at closing time Tuesday, trying to catch up with transactions which hit nearly 15 million shares for day, highest total since 1929." Yale Joel—Time & Life Pictures/Getty Images  Not originally published in LIFE. Tense scene at a brokerage office during the 1962 stock market "flash crash." John Dominis—Time & Life Pictures/Getty Images  Not originally published in LIFE. The NYSE during the 1962 "flash crash." Yale Joel—Time & Life Pictures/Getty Images  Not originally published in LIFE. The NYSE during the 1962 "flash crash." Yale Joel—Time & Life Pictures/Getty Images  Not originally published in LIFE. The NYSE during the 1962 "flash crash." John Dominis—Time & Life Pictures/Getty Images  Not originally published in LIFE. The NYSE during the 1962 "flash crash." Yale Joel—Time & Life Pictures/Getty Images  Not originally published in LIFE. The NYSE during the 1962 "flash crash." Yale Joel—Time & Life Pictures/Getty Images  Not originally published in LIFE. The NYSE during the 1962 "flash crash." John Dominis—Time & Life Pictures/Getty Images  Not originally published in LIFE. The NYSE during the 1962 "flash crash." Yale Joel—Time & Life Pictures/Getty Images  Page spreads from June 8, 1962, issue of LIFE. Life Magazine  Page spreads from June 8, 1962, issue of LIFE. Life Magazine  Page spreads from June 8, 1962, issue of LIFE. Life Magazine  Page spreads from June 8, 1962, issue of LIFE. Life Magazine  Page spreads from June 8, 1962, issue of LIFE. Life Magazine  Page spreads from June 8, 1962, issue of LIFE. 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