Amazon's quarterly earnings and outlook fell short of analysts' expectations yesterday, though, the company's revenue shot 22 per cent and margins remained strong during the key holiday quarter.
The stock initially slid then rose higher in extended-hours trading.
Chief executive Jeff Bezos highlighting the Kindle's e-book business, called it a multi-billion dollar category that expanded 70 per cent in 2012,while the traditional physical book business was up around 5 per cent during the same period, he noted.
Bezos said in the company's results statement, that the company was now seeing the transition it had been expecting.
Profits have fallen in recent years as the company invested for longer-term growth, and built fulfillment centres, developing a Kindle Fire tablet hardware in competition with Apple and expanding into internet-based cloud services.
The fourth-quarter profit results point to the possibility of Amazon being able to generate attractive returns from such spending according to analysts.