Amazon delivers big profit boost, but misses forecast

US online giant Amazon on Thursday reported a doubling of profits in the past quarter, lifted by its membership service and video, but the results fell short of Wall Street forecasts.

Amazon shares slid 11 percent in after-hours trade on the results, which showed a fourth-quarter profit of $482 million, up from a $214 million profit a year earlier.

The results marked the third consecutive quarterly profit for the company, which is a heavyweight in online retail as well as cloud computing, and more recently streaming video.

Overall revenue jumped 22 percent from a year ago to $35.7 billion.

Amazon, which earned a reputation for making little or no profit as it gained market share, managed an annual profit for 2015 of $596 million.

Revenues were up 20 percent for the year, at $107 billion.

"Twenty years ago, I was driving the packages to the post office myself and hoping we might one day afford a forklift," said chief executive Jeff Bezos, who founded the company in 1994.

"This year, we pass $100 billion in annual sales and serve 300 million customers. And still, measured by the dynamism we see everywhere in the marketplace and by the ever-expanding opportunities we see to invent on behalf of customers, it feels every bit like Day One."