What is Amazon hiding?

Amazon last week reported strong sales and earnings last week, with sales up 46%, operating income up 62% and net income 68% above figures a year ago. Some investors were disappointed at a decline in gross margin, but otherwise it’s a very impressive quarter.

However, as usual, it gave no information about sales of Kindle hardware or content.

As I did in December 2008, I wonder: what is Amazon hiding? We have quarterly and even first weekend sales for iPhones and iPads from Apple, a $45 billion/year member of the Fortune 500 that’s far bigger than Amazon (almost 2x revenues, 9x profits).

We also have the number of smartphones sold by Nokia, the number of PCs sold by HP and Dell — not to mention the number of Toyota, Ford and GM cars sold last week.

Some speculate that the Kindle sales are buried in the 72% ($1.5 billion) growth in “Electronics & Other General Merchandise” to $3.51 billion, although some of that is presumably due to last year’s acquisition of Zappos.

At the end of 2009, CEO Jeff Bezos said “millions” of Kindles have been sold. Assuming 2 million as the upper limit, at $250 each that’s $0.5 billion on 2009 sales of $24.5 billion. So I suppose until sales are 5x as big (proportionately), Amazon will be able to postpone honest disclosure of how the Kindle is really doing.

Once we get Kindle sales, perhaps Barnes & Noble will level with us on Nook sales. I’m not holding my breath.

Update Monday 11am: Taiwanese news site Digitimes concludes that the Nook gained 53% of US e-book shipments in March 2010, surpassing Kindle. It estimates 2009 global e-reader sales at 3.8 million, projecting 11.4 m in 2010. Hat tip: Jay Yarrow, Forbes.