New York Stock Exchange suspends trading in all securities

Equity trading was halted Wednesday at the New York Stock Exchange as the biggest American share venue addressed a computer malfunction and canceled open orders.

“We’re currently experiencing a technical issue that we’re working to resolve as quickly as possible,” Marissa Arnold, an NYSE spokeswoman, said in an e-mailed statement. “We will be providing further updates as soon as we can, and are doing our utmost to produce a swift resolution, communicate thoroughly and transparently, and ensure a timely and orderly market re-open.”

Stocks stopped trading on the exchange’s platform at about 11:32 a.m. in New York. They continued to change hands on other venues such as the NASDAQ Stock Market and Bats Global Markets.

Kevin Callahan, a spokesman for the Securities and Exchange Commission, declined to comment.

The NYSE is one of 11 exchanges and more than 50 private venues where American stocks change hands. While Wednesday's issue affected transactions on the company’s main market and impacted indexes derived from prices generated by that venue, investors could still buy and sell stock elsewhere.

“You can still execute NYSE stock,” said Michael Antonelli, an institutional equity sales trader and managing director at Robert W. Baird & Co. in Milwaukee. “Other venues are still available. Dark pools are still available. It certainly affects pricing of the Dow.”

The NYSE plays a dual role in the U.S. equity market, acting as a venue on which investors buy and sell shares and also in an administrative and listing capacity that oversees two of the three official price feeds for American stocks. Those feeds, known as Tape A and Tape B, continued to operate.

“For the most part the system is muddling along, relatively normally,” said Steve Sosnick, an equity risk manager at Timber Hill, the market-making unit of Greenwich, Connecticut-based Interactive Brokers Group Inc. “There’s no shortage of other places that are open and trading at this point.”

Sosnick said the firm was tweaking its order routing but beyond that “things are relatively normal.”

“We’re getting price information from other venues,” Sosnick said. “We haven’t come to a halt by any means and the options exchanges are up.”

A U.S. Department of Homeland Security official, who spoke on condition of anonymity, said there was no indication so far that the NYSE had been hacked.

While the halt recalled the August 2013 outage in NASDAQ-listed securities, when a broken price feed forced the exchange to stop trading in more than 2,000 listings for several hours, its immediate impact was not as great because trading continues today on other venues. That event caused SEC Chair Mary Jo White to call the heads of all the public equities exchanges to stress the importance of stability in U.S. markets.