Amazon disappointed investors with its fourth quarter results, yet was unsurprisingly bullish about its performance and prospects.
Net sales had increased by 40 per cent, hitting $34.2 billion (21.6 billion), compared with $24.51 billion in 2009, but this was below what analysts had predicted.
Operating income increased 25 per cent to $1.41 billion, compared with $1.13 billion in 2009. Net income went up by eight per cent to $416 million.
Whilst profits had gone up by eight per cent, Amazon shares had fallen on Wall Street.
"We had our first $10 billion quarter, and after selling millions of third-generation Kindles with the new Pearl e-ink display during the quarter, Kindle books have now overtaken paperback books as the most popular format on Amazon.com," said Jeff Bezos, founder and chief executive (CEO) of Amazon.com.
"Last July we announced that Kindle books had passed hardcovers and predicted that Kindle would surpass paperbacks in the second quarter of this year, so this milestone has come even sooner than we expected - and it's on top of continued growth in paperback sales."
The company revealed it was selling more Kindle books than paperback books.
For every 100 paperback books Amazon had sold, the firm has sold 115 Kindle books.
The cloud side of the company, Amazon Web Services, recently launched a new bulk email service targeted at businesses and developers.
