A technical error at the New York Stock Exchange NYSE resulted in the suspension of trading of about 200 securities. The glitch occurred soon after the start of trading at 9:30 a.m. E.T. with many efforts from the NYSE at that time to resolve the issue, the spokeswoman said. NYSE first alerted traders to a “technical issue” at one of its trading units about 17 minutes after the opening bell in New York. It resolved the problem, but then it flared up again by 10:26 am ET. An hour later, the exchange operator upgraded the severity of the problem to “critical” and suspended trading in 199 tickers on the NYSE, report Adam Samson and Nicole Bullock in New York. The malfunction had affected just about 4% of NYSE-listed securities. Stocks that were suspended on the Big Board got rerouted to other exchange venues, including NYSE Arca, and NYSE-run trading platform in order for them to resolve the malfunction.

Some of the groups that were affected are Fortress Investment Group (FIG) -1.03%, Agree Realty Corp. (ADC) -1.16%, Graco Inc.(GGG) -1.19%, OneMain Holdings Inc. (OMF)-3.75%, Townsquare Media Inc. (TSQ) -2.50%, and BlackRock Resources & Commodities Strategies Trust (BCX), -0.27% . According the Kristen Cause, the official spokesperson of the NYSE confirmed that orders related to those impacted securities have been cancelled.  It wasn’t exactly clear when the technical snafu will be fixed.

“NYSE experienced a technical issue in one trading unit, which affected a subset of symbols listed on our Market Status website here. All open orders, including MOC and LOC orders, were cancelled. Trading has resumed in those symbols at 1:17 pm ET and all systems are now operating normally,” the NYSE said in its systems status page.

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Both the NASDAQ and BATS stock exchanges had declared self-help against the NYSE amid the technical problems. A self-help exception allows trading centers to bypass an automated trading center that is experiencing system problems, according to the SEC.

NYSE believes Citadel KCG traded the stocks affected at Post 5, confirmed NYSE spokesperson Kristen Cause. The area of the trading floor was roped off as the issue was addressed. Cause told CNBC that she believes the issue is linked to the NYSE’s own system but it will continue to look for the root cause. The list includes groups like Nucor, a $14.9 bn steel products maker, and MGM Growth Properties, a real estate investment trust that made its public debut on the NYSE last month.

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“We are investigating the root cause and then we will implement a fix as soon as we can,” the spokesperson said, adding, “the goal is to reinstate these securities by the close.”The symbols involved securities with KCG, a designated market maker, but NYSE stressed that the problem was an exchange issue. The New York Stock Exchange had resolved the critical technical issue that led to 200 ticker symbols being suspended for trading after the glitch took place but still looking for the main cause.