His company (Microsoft) which as you know puts out buggy, expensive software, get so many tax breaks that during many years, they don’t pay any income taxes at all.
This excerpt from the book Radical Possibilities by Jean Anyon gives a little history of what’s been happening to taxes in the US over the past 150 years. I recommend it. Here are a couple of pages. The part listing companies that don’t pay any taxes at all (including Microsoft, GE, Colgate-Palmolive) is near the end.
If you want to look up the sources cited in this article, go ahead and click on the Amazon link I provided above (or else here), and then click on “search inside” the book image that will appear. The first source cited comes from the following book, which I haven’t read, but looks interesting: