Amazon.com says its fourth-quarter net income fell 45 percent, as higher revenue failed to keep pace with increased spending on order fulfillment and digital content.

Amazon.com Inc. said Tuesday that it earned $97 million, or 21 cents per share, in the October-December period. That's down from $177 million, or 38 cents per share, in the same period a year earlier.

Revenue at the world's biggest grew 22 percent to $21.27 billion from $17.43 billion.

FactSet says analysts had expected earnings of 28 cents per share on revenue of $22.26 billion.

For the current quarter, Amazon expects revenue of $15 billion to $16.6 billion. Analysts had expected revenue of $16.86 billion.

Nonetheless, Amazon's stock is up 5 percent in after-hours trading in the heels of the announcement.

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