Looking for a co-founder? Don’t draw from this pool

When people choose their cofounder, it’s rarely scientific. They’re guided by trust, and trust is easiest to find in familiar places: former coworkers, college classmates, close friends, people who already sit in your orbit. While starting a company is chaotic enough without bringing strangers into the mix, I wanted to understand whether this instinct toward familiarity actually comes with a cost. Turns out it does. Having worked with hundreds of early-stage startups as founders and investors, including at Coatue, Kleiner Perkins, and NFX, we wanted to test whether the instincts founders use to choose partners actually hold up in the data. We surveyed nearly 350 U.S. tech IPOs and more than $1 billion in exit outcomes over the past 20 years to complete the Outcast Billion-Dollar Founder Study. This report analyzes founder count, prior relationships, startup experience, age at founding, and more. We then compared these variables against exit valuation and time to liquidity, linking veri