Computer glitch causes confusion by showing insane stock market changes

At other times, the market data reset shares in major corporations like Apple, Google, and Microsoft to $123.47 (109 euros) each. It was triggered after financial information providers wrongly interpreted a Nasdaq data test as live prices, leading to brief pandemonium on trading floors. For Amazon, that would mean shares finished the day down 87 percent when in actuality AMZ finished the day down 1.5 percent at $953.66. Amazon's opening price, for instance, is $972.79 per share - it's a long way down to $123.47 and would've been catastrophic.

USA stock markets were open for half a day on Monday and are closed Tuesday for Independence Day.

Nasdaq added "unlisted trading privileges", a right granted by the Securities and Exchange Commission allowing exchanges to facilitate trading of stocks listed on other official United States exchanges as well, may have been a factor in the error.

Nasdaq later issued a statement to the Financial Times that this error was caused due to "improper use of test data".

Popular finance websites, including Google Finance, Yahoo Finance and Bloomberg, have mistakenly shown a crash in Amazon.com Inc. and Apple Inc. stocks Monday evening. Third-party data providers such as Google Finance and Yahoo Finance displayed the altered information.

On the bright side, at least the wrong prices appeared on a holiday when the market had closed. Joe Christinat, a Nasdaq spokesman, said no actual trades were affected by the glitch.

By early Tuesday, the correct data was starting to appear on the websites affected. Nasdaq is working with UTP and third parties to resolve the matter.

  • Eleanor Harrison