Amazon.com has reported a profit near $US2 billion ($A2.8 billion), the largest in its history, as the online retailer drew millions of new customers to its Prime fast-shipping club for the holiday season and as changes to US tax law added to its bottom line.
Shares rose more than 6 per cent in extended trading, after previously closing down 4 per cent on the Nasdaq.
Seattle-based Amazon is using fast shipping, television shows exclusive to its website and forays into new technology, such as its voice-controlled Alexa devices, to attract high-spending Prime members. Amazon said price cuts at Whole Foods Market, which it acquired for $US13.7 billion last year, are helping it win grocery sales, too.
The world's largest online retailer said net income more than doubled to $US1.86 billion, or $US3.75 per share in the fourth quarter ended December 31. Its profit received a provisional $US789 million boost from the US Republican tax bill passed in December. Analysts on average were expecting just $US1.85 per share, according to Thomson Reuters I/B/E/S.
"This was another blow-out quarter for Amazon," said GBH Insights analyst Daniel Ives. "The retail strength was eye-popping as the company had a banner holiday season and looked to capture roughly 50 per cent of all e-commerce holiday season sales."
As expected, the period running from before the US Thanksgiving holiday through New Years was Amazon's biggest-ever by revenue. Sales rose 38 per cent to $US60.5 billion in the quarter, beating estimates.
The company's fast delivery, like its two-hour Prime Now service, has helped win over holiday shoppers eager to avoid the crowds. Prime saw more than 4 million sign-ups in one week alone last quarter, and revenue from subscription fees grew 49 per cent to $3.2 billion, Amazon said.
Some 60 million, or close to half of all US households, are estimated to have Prime subscriptions.
The surprise star of the past quarter was Amazon's voice aide Alexa, embedded in the company's Echo speakers and Fire TV players, as well as some cars and house gadgets. Millions of Amazon customers ordered goods by voice with Alexa in the past year, said Brian Olsavsky, Amazon's chief financial officer.
"Our 2017 projections for Alexa were very optimistic, and we far exceeded them," added Jeff Bezos, Amazon's founder and chief executive, in a statement.
