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 ).

Though a small part of Amazon’s total revenue, AWS is a key driver of Amazon’s profits, typically accounting for about 60 per cent of the company’s overall operating income. AWS reported 16.9-per-cent growth in the first quarter.

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.