New York Stock Exchange blames manual error for Tuesday trading glitch

The New York Stock Exchange on Wednesday blamed a manual error involving its disaster recovery systems for causing chaos during the previous day’s market open.

Two-thirds of NYSE-listed securities started trading on Tuesday without having held an auction to determine their opening price, leading to sudden swings in many blue-chip stocks and mass confusion among traders.

The exchange confirmed on Wednesday morning that it would cancel more than 4,300 trades in 251 different stocks.

Shares in big, well-known companies, such as AT&T and Wells Fargo, experienced huge surges or plunges in value as markets opened, before trading was halted seconds later. A total of 84 stocks hit limits that are designed to stop securities from trading at extreme prices.

In a separate update on Wednesday morning, NYSE also said that 81 stocks including Morgan Stanley and Snap had “erroneously” had short-selling restrictions applied.

“I haven’t seen anything this crazy technology-wise in 30 years in the industry,” said one trader who works on the NYSE floor. “It was pretty chaotic.”

NYSE chief operating officer Michael Blaugrund said on Tuesday evening that “such events are extremely rare”, and Wednesday’s market open appeared to go smoothly.

The S&P 500 was down 1.6 per cent in mid-morning trading on Wednesday, while the Nasdaq Composite was 2.2 per cent lower.