(Reuters) -Amazon.com topped Wall Street estimates for quarterly revenue on Thursday, as strong sales over the holiday shopping season boosted its retail business, helping offset weakness in the cloud computing unit.

Shares of the company fell 2% in extended trading.

The company's cloud unit, Amazon Web Services (AWS), reported a 19% rise in revenue to $28.79 billion, falling short of estimates of $28.87 billion, according to data compiled by LSEG. Amazon joins smaller cloud providers Microsoft and Google in reporting weak cloud numbers.

The cloud weakness comes at a time when investors have grown increasingly impatient with Big Tech's multibillion-dollar capital spending and are hungry for returns from the hefty AI investments.

Still, Amazon's retail business helped offset the cloud weakness, with the company reporting online sales growth of 7% in the quarter to $75.56 billion. That compared with estimates of $74.55 billion. 

The company reported revenue of $187.8 billion in the fourth quarter, compared with the average analyst estimate of $187.30 billion, according to data compiled by LSEG.