Amazon's stock went up more than 6 percent in after hours trading.
Here are the most important numbers:
Amazon's revenue, which includes sales from Whole Foods, jumped 38 percent year-over-year. Its North America revenue jumped 42 percent to $37 billion, while international sales grew 29 percent to $18 billion.
In a call with analysts, Amazon's CFO Brian Olsavsky credited record order volume and improved warehouse efficiency during the busy holiday shopping season for the successful quarter. He also pointed out AWS's continued expansion and said the advertising business was a "key contributor" in North American revenue growth.
Net income was $1.9 billion, more than double from the same period of last year and the highest in company history. Amazon noted that the fourth quarter earnings includes a tax benefit of roughly $789 million due to the change in U.S. tax code.
Amazon's cloud unit, AWS, continued to be the growth driver of the company. For the quarter, AWS sales jumped 45 percent year-over-year, while generating $1.3 billion in operating income, a whopping 64 percent share of Amazon's total operating income.
In a statement, Amazon CEO Jeff Bezos touted the success of Amazon's voice-controlled technology Alexa and hinted that the company would invest more in the space.
"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," Bezos said.
First quarter revenue guidance came in the range of $47.75 billion to $50.75 billion, above street estimates of $48.6 billion. But operating income guidance was between $300 million to $1 billion, below the $1.5 billion street consensus, likely indicating heavier investments going forward.
Amazon has been in heavy investment mode in recent quarters, pouring money into warehouse and data center expansion, while adding more video content for its Prime Video offering. Its total costs jumped 38 percent in the fourth quarter year-over-year, to $58 billion, a significant jump from the 23 percent cost increase between the fourth quarter of 2015 and 2016.
Physical stores revenue, which primarily comes from Whole Foods, came in at $4.5 billion. This is the first full quarter to have Whole Foods revenue included in Amazon's sales, and Olsavsky said the company's "very happy" with the initial results of the grocery chain.
For the full year, Amazon had $177.9 billion in sales, up 31 percent from the previous year's $136 billion. Still, the company continued to invest in its business, resulting in a 2 percent drop in its operating profit to $4.1 billion.
Amazon stock is up more than 70 percent over the past year, and hit the $700 billion market cap milestone for the first time this week.
*Correction: Amazon's EPS number is not comparable against earnings estimates because of the tax benefits the company saw due to changes in the U.S. tax code.