Betterment: Jon Stein

When Jon Stein realized he couldn't stand the sight of blood, he gave up the idea of becoming a doctor. Instead, he went into finance, but soon grew restless with "helping banks make more money." So he decided to build a business where he could help everyday investors make more money: an online service that would use a combination of algorithms and human advisers. Jon launched Betterment at a precarious time — shortly after the financial crash of 2008. But today, the company has roughly 13 billion dollars under management. PLUS in our postscript "How You Built That," how Gerry Stellenberg combined his knack for technology and his love for pinball to create the P3: a pinball machine that allows a real-life ball to interact with virtual objects.