Here's data on equity ownership at the time of IPO for 258 companies: http://www.slideshare.net/lebret/equity-in-258-high-tech-start-ups-lebret-mar2014 http://w

Here's data on equity ownership at the time of IPO for 258 companies: http://www.slideshare.net/lebret/equity-in-258-high-tech-start-ups-lebret-mar2014 http://www.slideshare.net/lebret/equity-in-258-high-tech-sta... The average overall was 7.6%, but it varies a lot, from close to 0% (Zipcar) up to 28% (Amazon).