The New York Stock Exchange unexpectedly shut down trading in all of its listed stocks late Wednesday morning.
The exchange said on Twitter: “The issue we are experiencing is an internal technical issue and is not the result of a cyberbreach.”
A trader on the floor of the exchange in lower Manhattan, who spoke on the condition of anonymity, said that after the suspension began, traders were told that the problem was related to updated software that was rolled out before markets opened on Wednesday.
According to the trader, the exchange said that the new software caused problems soon after trading began on Wednesday and the exchange decided to shut down trading all together to fix the problem.
A representative for the exchange did not respond to a request for comment on the trader’s account.
Still, in the hours before the outage, the New York Stock Exchangeannounced that it was working on an issue with “gateways” that was making it impossible to receive information and cancel orders for some trades.
After the shutdown began, the exchange said on Twitter: “We chose to suspend trading on N.Y.S.E. to avoid problems arising from our technical issue” — though it did not specify the problem.
On the floor on Wednesday, people were angry and were waiting around for their customer orders to be canceled by the exchange, the trader said.
The New York Stock Exchange, which is now owned by Intercontinental Exchange, has had, like other stock exchanges, technical difficulties in the past, but the scale of the problem on Wednesday has little precedent.
Stocks listed on the New York Stock Exchange — the world’s largest stock exchange based on market capitalization — continued trading on other exchanges, like Nasdaq.
