NYSE glitch caused irregular share prices

On January 24, 2023, a system issue caused 251 securities to be traded without an opening price and before the receipt of Limit Up Limit Down bands. 

Before trading begins on a security each day, the opening price for that security is calculated using pending buy and sale orders. Immediately after trading begins, limit up and limit down (LULD) bands are set to prevent stocks from being traded outside of certain price ranges.

These two things didn’t occur for these 251 securities. As a result, investors were able to place orders at prices that were sometimes much higher or lower than the previous day’s closing price.

As an example, Walmart (WMT) closed at $142.64 on January 23, 2023, but opened at $159.88 the next morning. Walmart’s shares have not traded for for this price since April 21, 2022, when the day’s trading price was as low as $158 and as high as $159.87. For January of 2023, Walmart’s stock has been trading in the low $140s. In December, the stock had only reached the $150 mark on one day, and that was five days after a dividend payout. On that day, the stock was as $150.20. 

The NYSE has ruled that these trades are eligible under NYSE Rule 7.10(c)(1)(B) to be reviewed as Clearly Erroneous.

Some brokers have already notified customers that their affected trades would be canceled.