One of the most widespread rules of thumb in the venture industry is about the number of startup founders. It implies that an optimal number of founders is 2 or 3, startups with a solo founder are OK-ish, startups with 5 or more founders are rotten. Is this belief based on a solid foundation? It’s not. CrunchBase data indicates the opposite: the more founders a startup has, the better its chances are to raise money and have an exit.