The New York Stock Exchange is investigating why trading was briefly halted for dozens of companies Tuesday just after the market opened.
Major names impacted included Verizon, McDonald’s, Morgan Stanley, AT&T and Nike, according to the NYSE.
Many of those stocks made large moves just minutes into the morning trading session, sending companies like Wells Fargo and Morgan Stanley into a nosedive.
Morgan Stanley briefly plunged to $84.93 after ending at $97.13 on Monday before recovering. McDonald’s and Walmart also fell more than 12% before trading was halted. Those drops may have triggered volatility halts on the exchange.
NYSE, and most other major stock exchanges, issue automatic halts for stocks that move dramatically up and down.
In May 2010, the Dow plunged during a “flash crash,” before dramatically rebounding. A report by US regulators later said the huge swing was the result of high-frequency trading activity following a massive trade by a single market participant. That sparked a number of regulatory changes aimed at safeguarding the equity markets, including a “limit up-limit down” mechanism that prevents trades in individual stocks from swinging outside a specific price band.
But exchange officials can also halt trading when there is a technical problem. Last fall, three Canadian stock exchanges suffered a 40-minute outage due to a “connection issue,” before the exchange was able to isolate and repair the problem.
By 9:50 a.m. ET Tuesday all affected companies on the NYSE had resumed trading, according to a status report from the NYSE that said “all systems are currently operational.”
NYSE officials told CNN the exchange “continues to investigate issues with today’s opening auction.”
In a emailed statement, exchange officials said opening auctions “did not occur” for a number of stocks. The exchange, they wrote, is working to clarify which stocks were impacted.
“Impacted member firms may consider filing for Clearly Erroneous or Rule 18 Claims,” they added, meaning companies that saw their stocks halted can seek reimbursement for losses resulting from NYSE system failures.