(Reuters) -Amazon.com shares dropped nearly 8% 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 and Microsoft.

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.

Amazon.com Inc. dropped in premarket trading after projecting weaker-than-expected operating income and trailing the sales growth of its cloud rivals, leaving investors searching for signs that the company’s huge investments in artificial intelligence are paying off.