The Inc. Magazine Bill’s excellent adventure (meaning Bill Gates of Microsoft) and the state of the small business software market. According to Gartner, 90% of small and midsize businesses run on the Microsoft platform. That’s a stranglehold on this enormous market of 8 million companies in the U.S. and 40 million worldwide. Globally, these companies pay almost as much for info tech – $400 billion a year – as US spends on defense.