Amazon.com Inc. stock was down more than 4% in after-hours trading Feb. 2 after the company reported revenue below expectations for the fourth quarter of 2016.

The online retail giant's fourth-quarter 2016 net sales came to $43.74 billion, up 22% from $35.75 billion in the prior-year quarter. Excluding foreign exchange impact, net sales would have grown 24% year over year. For full year 2016, net sales totaled $135.99 billion, up 27% from $107.01 billion reported in 2015. Full-year net sales grew 28% adjusting for foreign exchange impact.

While the quarterly revenue numbers were in range of the company's previously provided guidance, the total was below consensus expectations of $44.70 billion in fourth-quarter revenue, according to S&P Capital IQ.

Amazon beat EPS expectations, posting quarterly net income of $749 million, or $1.54 per share, up from $482 million, or $1.00 per share, in the year-ago period. For full year 2016, the company saw $2.37 billion in net income, or $4.90 per share, compared to $596 million, or $1.25 per share, in 2015.

The S&P Capital IQ consensus GAAP EPS estimates for the fourth quarter and full year 2016 were $1.40 and $4.76, respectively.

Amazon CEO Jeff Bezos was bullish on the company's Prime service, which expanded to more than 200 countries and territories in December 2016. "Prime members can now choose from over 50 million items with free two-day shipping — up 73% since 2015," the CEO said in a statement in the earnings release.

Looking ahead to the first quarter of 2017, Amazon expects net sales to range between $33.25 billion and $35.75 billion, an estimated year-over-year increase of 14% to 23% from the comparable 2016 quarter. The guidance anticipates an unfavorable impact of about $730 million or 250 basis points from foreign exchange rates.

Operating income is expected to be between $250 million and $900 million, compared with $1.1 billion in first quarter 2016.