Amazon.com shares fell about 7 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, 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. That disappointing growth came even as