I’ve had several accounting students inquiring about sources for ratios for companies and industries, particularly Amazon, for a group presentation. I have been suggesting that they consult the following Subject Guides that Louise prepared:
http://guides.newman.baruch.cuny.edu/content.php?pid=62304&sid=458501; and http://guides.newman.baruch.cuny.edu/content.php?pid=58524&sid=428826
I’m also suggesting a search for Amazon on Edgar Online I-Metrix. If you do a company search for Amazon (or other companies) and look in the left column under Financials, Ratios are listed. This database also allows one to compare companies.