Normal trading resumed late Monday morning after the New York Stock Exchange said a technical issue had led to large fluctuations in the prices displayed for certain stocks, including Warren Buffett’s Berkshire Hathaway.

A little after 11 a.m. ET, the NYSE said the issue involved the market’s main electronic stock price publisher, but that most stocks had since reopened or were in the process of reopening.

“Shortly before noon, the issue was resolved and trading in the impacted stocks resumed,” the exchange said in a statement. “The NYSE is reviewing potentially impacted trades.”

In a statement, the publisher, Consolidated Tape Association, said the issue may have been related to a software update that impacted price ‘bands’ or the electronic guardrails that limit volatility. It said it had resolved the issue by reverting operations to a data center where the previous software was still in use.

Some 50 stocks were affected, the website indicated, and trades in those companies were halted for about an hour.

The issue caused the NYSE to incorrectly show so-called Class A shares of Berkshire down 99% from their price of about $620,000 a share. Those shares resumed trading at normal levels around 11:35 a.m. ET.

Other shares affected included AMC Entertainment, Chipotle and GameStop.

Earlier, GameStop shares soared after trader Keith Gill, known as ‘Roaring Kitty’ on social media, apparently posted that he was increasing his bet on the stock.