A bizarre computer glitch sent shares in dozens of US technology companies including Apple, Amazon and Microsoft to the same price on Tuesday morning, leading some to apparently lose billions in market value.

The bug showed many stocks on the Nasdaq exchange to briefly be reported as $123.47 on Bloomberg, Reuters and Google Finance data. It was triggered after financial information providers wrongly interpreted a Nasdaq data test as live prices, leading to brief pandemonium on trading floors.

Amazon's shares were shown falling from almost $950, a drop of 87 per cent, Google owner Alphabet's fell by 86 per cent and Apple fell by 14.3 per cent.