Amazon.com forecast third-quarter sales above market estimates on Thursday but failed to live up to lofty expectations for its Amazon Web Services cloud computing unit after rivals handily beat expectations.

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.com shares fell seven per cent on Friday as the tech giant’s results fanned investor fears its cloud unit was falling behind Microsoft and Alphabet in the artificial intelligence race. Amazon Web Services,