Amazon.com shares AMZN.O fell 7% 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.

The UK’s cloud computing market is “not working well” and conduct requirements should be considered for the sector’s two main players, Microsoft and Amazon, according to the competition watchdog.The final report from an independent inquiry group of the Competition and Markets Authority (CMA) has found that Microsoft and Amazon Web Services (AWS) are hurting competition in the cloud computing sector.

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.