NEW YORK (TheStreet) -- Amazon (AMZN) - Get Amazon.com, Inc. Report shares surged after the online retail giant reported better-than-expected earnings per share for the fourth quarter.

The Seattle-based company reported revenue of $29.33 billion, up 15% from a year ago, while net income fell to $214 million from $239 million. But earnings per share were 45 cents, down from 51 cents a share a year ago, though well above analysts expectations of 17 cents a share.

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Amazon shares were up more than 8% in after-hours trading.

While some were hopeful that Amazon would finally share numbers on Prime membership, it maintained its air of secrecy, while repeating its statement that there are tens of millions of members and divulging that worldwide paid membership grew 53% last year and in the U.S. alone, grew 50%.

"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. The data [are] in and customers agree," said Amazon CEO Jeff Bezos. "Prime is a one-of-a-kind, all-you-can-eat, physical-digital hybrid -- in 2014 alone, we paid billions of dollars for Prime shipping and invested $1.3 billion in Prime Instant Video. We'll continue to work hard for our Prime members."

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Amazon's operating income was $591 million in the quarter, compared with $510 million a year ago.

Net sales for the whole year increased 20% to $88.99 billion, compared with $74.45 billion in 2013. Operating cash flow increased 25% to $6.84 billion for the year ended Dec. 31, 2014, and free cash flow for the year decreased to $1.95 billion, down from $2.03 billion in 2013.

The year still ended with a net loss of $241 million, or 52 cents per diluted share, compared with 2013's net income of $274 million, or 59 cents per diluted share.

Looking forward to the next year, Amazon predicts that the first quarter's net sales will be between $20.9 billion and $22.9 billion, with an operating income ranging from a loss of $450 million to earnings of $50 million. The company said this week that it would be launching a corporate email and calendar service.

--Written by Rebecca Borison in New York

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