Amazon's shares jumped 6% after the retail giant posted its financial results for the fourth quarter (ended 31st December 2017) revealing it doubled profits made in the same period last year to $1.9bn (£1.34bn).
As well as achieving record quarterly net income - $3.75 per share - the company's revenues (including sales from Whole Foods, acquired last year) rose 38% to $60.5bn (£42.53bn).
International fourth-quarter net sales rose from $13.965bn in 2016 to $18.038bn in 2017.
The company benefitted from a $789m tax benefit after a change in US tax law in 2017, it noted.
Full year revenue rose 31% to $177.9bn (£124.6bn) compared with $136bn in 2016, while profit reached $3bn versus $2.4bn in 2016.
Among Amazon's highlights of 2017, the company said it had shipped more than five billion items with Prime worldwide, and that more new paid members had joined Prime in 2017 than in any previous year, both worldwide and in the US.
Jeff Bezos, Amazon founder and c.e.o., said the company would now "double down" on Alexa, its intelligent personal assistant, after revealing it "far exceeded" sales projections in 2017.
"Our 2017 projections for Alexa were very optimistic, and we far exceeded them. We don't see positive surprises of this magnitude very often -- expect us to double down," he said. "We've reached an important point where other companies and developers are accelerating adoption of Alexa. There are now over 30,000 skills from outside developers, customers can control more than 4,000 smart home devices from 1,200 unique brands with Alexa, and we're seeing strong response to our new far-field voice kit for manufacturers. Much more to come and a huge thank you to our customers and partners."
Amazon also celebrated the 10th anniversary of Kindle in 2017 by releasing a new model, the Kindle Oasis.