The 9 richest billionaires who earned their fortunes in tech

Nearly a third of the 30 richest billionaires on the recently relaunched Bloomberg Billionaires Index have one major thing in common: They earned their fortunes in technology.

That includes Microsoft founder Bill Gates, who retains his title as the richest man in the world, as well as Amazon's Jeff Bezos and Facebook's Mark Zuckerberg. Though US moguls dominate the world of tech billionaires, China's Jack Ma of Alibaba and Pony Ma of Tencent also earn spots in the top nine.

Tech money proves to be hard-earned as well: All nine of the richest billionaires are self-made, thanks to the powerful companies they built themselves, including Facebook, Microsoft, and Google.

For the ranking, Business Insider culled data from the Bloomberg Billionaires Index as of March 1, when the index relaunched in its expanded format. The index updates daily to provide up-to-the-minute data on the world's wealthiest men and women. You can read the full methodology here.

Below, read on to see the nine richest billionaires who made their fortunes in tech.