This article originally appeared as part of ongoing coverage in our premium Motley Fool Stock Advisor service ... we hope you enjoy this complimentary peek!

What's happening? 
Shares of (NASDAQ:AMZN) jumped more than 12% early Friday after the online retail juggernaut announced better than expected fourth-quarter results.

Why it's happening 
Quarterly revenue rose 15% year over year to $29.33 billion, which translated to adjusted net income of $214 million, or $0.45 per diluted share. Operating income came in at $591 million. Also note Amazon achieved this result despite an $895 million negative impact to revenue from year-over-year foreign exchange rate changes, excluding which Amazon's net sales would have increased by 18%.

In addition, operating cash flow jumped 25% over the same year-ago period to $6.84 billion for the trailing 12-months, while free cash flow fell around 4% to $1.95 billion. 

For perspective, three months ago Amazon told investors to expect net sales between $27.3 billion and $30.3 billion, or growth between 7% and 18%, and an operating result between a $570 million loss and income of $430 million. Analysts, on average, were expecting sales of $29.67 billion to result in earnings of just $0.17 per share.

There are many moving pieces to, from its burgeoning Amazon Web Services division to popular devices under its hardware segment including Fire TV and Kindle tablets. But CEO Jeff Bezos specifically gave props to the stellar contribution of Amazon Prime despite its price increase last year, saying "[On] a base of tens of millions, worldwide paid [Prime] membership grew 53% last year -- 50% in the U.S. and even a bit faster outside the U.S."

Finally, for the current quarter, Amazon says net sales should be between $20.9 billion and $22.9 billion, with an operating result in the range of a $450 million loss to income of $50 million. Analysts were modeling fiscal first quarter sales and earnings of $23.05 billion and $0.12 per share, respectively. But in the end, it's no wonder the market is in a forgiving mood considering Amazon just significantly exceeded even its own guidance for Q4.

Editor's note: The operating cash flow figure has been corrected to $6.84 billion for the trailing 12 months.