one in five billion-dollar companies was founded by a solo founder. That’s less common than dual founders (36 percent) or companies with three co-founders (28 percent), but more common than you might think. There are also a few cases where billion-dollar companies were started by more than three people: 12 percent of billion-dollar companies had four co-founders; a very small percentage had five or more. These numbers are similar to those in the random group, suggesting no specific advantage or disadvantage to any of these situations, including the solo-founder scenario.
I occasionally add a personal note to them.
The whole collection is available here.