Fortune's Top Ten

We are often in the habit of looking at America's biggest companies in terms of their market capitalization, but Fortune's venerable Fortune 500 list ranks corporations in terms of their revenues. That pushes the tech giants like Apple and Facebook down the list, in favor of the likes of Walmart, which is a clear No. 1 in this ranking. The top ten, with their 2017 revenues in millions:

1. Walmart $500,343
2. Exxon Mobil $244,363
3. Berkshire Hathaway $242,137
4. Apple $229,234
5. UnitedHealth Group $201,159
6. McKesson $198,533
7. CVS Health $184,765
8. Amazon.com $177,866
9. AT&T $160,546
10. General Motors $157,311

The least familiar name on that list is McKesson. What did they do to make $200 billion last year? McKesson sells medical supplies, pharmaceuticals, and other forms of medical technology.