Logan Green and John Zimmer, 31, 31
San Francisco’s perennial number-two ride-sharing company has had quite the year of its own: In 2014 revenue and total rides grew fivefold, it hired a full suite of C-level executives, and earlier this spring it raised a $530 million funding round, followed by another $150 million, most of which came from Carl Icahn and now values the company at $2.5 billion. Green and Zimmer joined forces in 2007 when they founded Zimride, a ride-sharing service started on the campus of Zimmer’s Cornell University. Lyft was started in 2012 as an on-demand extra but soon became their main focus; in 2013 they changed the name of the company and sold Zimride to Enterprise Holdings. This past year also saw the launch of Lyft Line, the company’s carpooling service critical to achieving the founders’ goal of providing affordable transportation on a scale that will compete with public transit. And in early September, the company announced a major partnership with China’s Didi Kuaidi—which also invested in the spring funding round.