Tracking share prices in real time is usually done via platforms like Bloomberg's, while others rely on Google and Yahoo Finance. Since many base trading decisions on the charts provided by those sites, it would help if they were accurate at all times. But yesterday a data glitch resulted in the Nasdaq reporting incorrect share prices for many high profile US tech stocks. About 16 stocks in total were affected including Apple, Microsoft, Alphabet, and Amazon.

The price for the affected stocks was set at $123.47 during the incident. This meant Alphabet and Amazon, both currently valued at nearly $1,000 per share, suffered a ~90% loss before the issue could be corrected. Microsoft on the other hand, whose stock currently trades for around $70, saw their shares soar nearly 80%.

The error occurred after US markets had closed, but still likely gave a fair share of traders a heart attack. While it appears that no trades were affected, the error momentarily wiped off hundreds of billions of dollars of market value for these companies.

What caused the temporary glitch? Nasdaq routinely distributes test data as part of their "unlisted trading privileges" service. The issue arose when several third parties displayed that test information live on their platforms. According to a spokesman to Business Insider, "as part of its normal process, the UTP distributed normal test data, and certain third parties improperly consumed and propagated that data." Following the incident, Nasdaq began working with UTP and the third parties to resolve the matter and ensure it doesn't happen in the future.

Screenshots obtained by Business Insider