Dozens of large-cap stocks saw their prices swing wildly at the open of trading Tuesday, sending companies including Wells Fargo & Co. and Morgan Stanley to brief but sharp plunges from which they mostly quickly recovered.
After closing Monday at $45.03, Wells Fargo fell as low as $38.10 before bouncing back, while Morgan Stanley plunged to $84.93 after ending at $97.13 on Monday.
Exchange officials didn't immediately respond to phone calls and emails. The price action bears hallmarks of past episodes in which computer malfunctions led to sudden price distortions.
"It's a little concerning," Oanda senior market analyst Ed Moya said by phone. "These are not your typical meme stock, easily manipulated companies, these are Morgan Stanley, Verizon, AT&T, these are some of the giants."
Tuesday's transactions occurred in New York Stock Exchange-listed securities and took place on other platforms, including ones overseen by CBOE Global Markets and private venues reporting to the Finra trade reporting facility.
At least 40 S&P 500 Index stocks were hit with trading halts, according to data compiled by Bloomberg. Other impacted shares included the likes of Walmart Inc. and McDonald's Corp. These stocks saw drops of at least 12% before they were halted. Their moves have now rebounded to less than 1% in either direction.
Episodes in which computer glitches lead to erratic pricing are rare on American exchanges but not unheard of. Perhaps the most famous was the August 2012 incident in which faulty software employed by one of the biggest market makers, Knight Trading, riddled exchanges with erroneous orders and sent shares swinging around the market.