Tech stocks appear to go nuts after computer glitch

The share prices of Amazon and other major tech companies appeared to go haywire on the eve of the July 4 holiday after a market data glitch.

Some websites showed Amazon (AMZN, Tech30) plunging 87%, Apple (AAPL, Tech30) dropping 14% and Microsoft (MSFT, Tech30) jumping 79% late Monday.

U.S. markets had closed early ahead of the holiday. But the crazy moves weren’t the result of wild after-hours trading, according to Nasdaq, the exchange where the stocks are listed.

Nasdaq said the misleading prices came from test data it sent out that was “improperly” used by some third party companies. It said it’s working with those companies to fix the problem as quickly as possible.

Nasdaq is working with third party vendors to resolve the matter as quickly as possible.
— Nasdaq (@Nasdaq) July 4, 2017

It was clear something odd was going on. Apple, Amazon and Microsoft’s share prices were all listed as exactly $ 123.47. So were those of eBay (EBAY) — up 254% — and video game developer Zynga (ZNGA) — up a staggering 3,292%.

The erroneous prices showed up on the websites of CNNMoney, Bloomberg and Google Finance. But they didn’t appear on Nasdaq’s own website.

That showed far more muted moves: Apple -0.3%, Amazon -1.4%, Microsoft -1%, eBay -0.9% and Zynga -0.3%.

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Nasdaq said the data that was sent out was part of “normal evening test procedures.”

It urged third party data providers to switch back to its official closing prices that were effective at 5:16 p.m. ET.