This is Cisco's model: two employees (or groups of employees) leave to develop some new tech, raising money and building staff in the process. In the end Cisco buys the one that gets traction and if the other fails the people can go back to Cisco.

It is a way of providing engineering bonuses without messing up the internal politics.

I have a neighbor who did this twice. Apparently that's not that common: I mentioned that in a random conversation once and the person I was talking to said "Oh, you live near XXX?"