NASDAQ announced that "improperly" processed test data by third-party vendors caused a glitch that crashes many stock prices of tech companies.
Popular stock sites such as MacOS widgets, Google Finance and Yahoo! Finance, all appeared to show stock prices at $123.47 each on Monday evening. Notable companies such as Apple, fell 14.3 percent. Google plunged more than 86 percent and Amazon had lost $398 billion in market capitalization.
In a statement, the American stock exchange said that "certain third parties improperly propagated test data that was distributed as part of the normal evening test procedures."
"For July 3, 2017, all production data was completed by 5:16 PM as expected per the early close of the markets," the statement continued. "Any data messages received post 5:16 PM should be deemed as test data and purged from direct data recipient's databases. UTP (Unlisted Trading Privileges) is asking all third parties to revert to Nasdaq Official Closing Prices effective at 5:16 PM."
The apparent price swings came on a day that the U.S. stock market closed three hours earlier than usual at 1 PM.
While some stock prices plummeted, some saw an extreme increase. For example, the online games group Zynga rocketed more than 3,000 percent. The swinging price concerned investors as many if them were checking to see what happened in after-hours trading.
In a 10 p.m. tweet, NASDAQ said that it's "working with third party vendors to resolve the matter as quickly as possible."
NASDAQ has had similar previous issues with its pricing data feed. In 2013 for example, the exchange halted all trading in its listed stocks for about three hours because of a fault with the feed.
