The ‘Eggs In One Basket’ Index

Earlier, I noted how Facebook’s advertising business generated 85% of its revenue last year, down from 95% in 2010, as its payments business is helping it diversify away from ads. Then I saw this post by Ed Bott, comparing Microsoft, Apple, and Google’s revenue by sources.

So I decided to chart up the “Eggs in One Basket” index, showing how much a handful of tech companies rely on their single biggest source of revenue. This covers each company’s most recently reported quarter, but not every company is the Dec. 2011 quarter.

There are obviously some fuzzy lines to draw — Microsoft’s Office business wouldn’t be much without its Windows business. And profits are a different story. But it’s a good, rough idea, I think. One big takeaway: Google really, really relies on its ad business.

Also: Apple’s Monster Quarter In Charts