Amazon.com ( AMZN-Q) shares dropped nearly 8 per cent before the bell on Friday, after growth in its cloud computing unit failed to impress investors, in contrast to the robust gains reported by AI-focused rivals Alphabet ( GOOGL-Q) and Microsoft ( MSFT-Q ).

Amazon Web Services, long the cloud-computing market leader, edged past Wall Street estimates for June-quarter revenue on Thursday with a 17.5 per cent increase, but it widely lagged the 39 per cent growth seen at Microsoft Azure and Google Cloud’s 32 per cent gain.

The tech giant expects total net sales to be between $174.0 billion and $179.5 billion in the third quarter, compared with analysts’ average estimate of $173.08 billion.