Amazon earnings: 45 cents a share, vs. expected EPS of 17 cents blew past Wall Street's earnings expectations on Thursday as holiday sales climbed some 15 percent, sending the company's shares rallying 14 percent in after-hours trading.

Amazon issued fourth-quarter earnings of 45 cents a share, down from 51 cents per share a year ago, but soaring past expectations of 17 cents.

Revenue rose 15 percent year-over-year, to $29.33 billion, but that trailed analysts' estimates of $29.67 billion. Excluding currency headwinds, the company said revenue increased 18 percent.

Amazon Prime, its annual membership program that costs $99 a year, was a bright spot for the e-commerce giant.

The company said worldwide Prime memberships grew 53 percent last year—up 50 percent in the U.S. and "even a bit faster" abroad.

"When we raised the price of Prime membership last year, we were confident that customers would continue to find it the best bargain in the history of shopping," said Jeff Bezos, founder and CEO of Amazon. "[I]n 2014 alone we paid billions of dollars for Prime shipping and invested $1.3 billion in Prime Instant Video."

Boxes move along a conveyor belt at an Amazon fulfillment center in Tracy, California.
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Boxes move along a conveyor belt at an Amazon fulfillment center in Tracy, California.

Operating income for the quarter totaled $591 million, up 16 percent from $510 million in the fourth quarter of 2013. During the company's earnings call, Amazon said first-quarter operating income could take a hit. Citing the unfavorable impacts of foreign exchange rates, Amazon projected that it could hand in an operating loss of $450 million or operating income of $50 million.

Amazon sees first-quarter sales of between $20.9 billion and $22.9 billion, falling below StreetAccount estimates of $23 billion.

Shares soared in extended-hours trading, but David Garrity, principal of GVA Research, said now is the perfect time to sell the stock.

"I think coming off of the fourth-quarter, which seasonally is the highest quarter for the company, we're going to see weaker numbers," Garrity said, citing Amazon's exposure to weaker economies overseas.

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The company is betting big on a handful of offerings, including Fire TV Stick, its speech recognition device,Echo, and a selection of cloud services.

Amazon Web Services, the company's cloud business, grew about 90 percent, year-over-year, to about 1 million active customers. The company plans to start bulking up that area sometime this quarter.

"We know there's going to be a point where they just don't need to build anymore servers and they can start to scale that business," said Michael Pachter of Wedbush Securities. "It's going to be a commodity business, meaning that its going to squeeze out all of the little guys; the only guys who can offer this is going to be guys with scale."

He predicted that the company could start to scale its cloud as early as 2017, which will cause its earnings to soar.

The company's operating margin was 2 percent during quarter that ended Dec. 31, 2014, unchanged from a year ago.

Frustrated investors have sent shares of Amazon down 19 percent in the past year even as the broader S&P 500 has risen 13 percent. The company is well-known for its razor-thin operating margins as the e-commerce giant plows money it earns back into new initiatives.