The commentary from the online shopping behemoth is in line with recent value-conscious consumer behaviour, ahead of retail giant Walmart's quarterly results later this month.

Amazon Chief Executive Officer Andy Jassy said on a post-earnings call that customers were trading down on price when they could.

The company's shares were trading at about $169 before the bell. Amazon was set to lose about $157 billion in market value, if the losses hold.

"Consumer spending trends facing retail peers appear to have finally caught up with Amazon's P&L," MoffettNathanson Analyst Michael Morton said.

Amazon's online stores sales rose 5% in the second quarter to $55.4 billion, compared with growth of 7% in the first quarter.

--Reuters--