In the last year or so, the unicorn phenomenon has really taken off. These private companies, seen as mythical and rare, are each worth at least $1B and include some of the world's fastest-growing tech firms.

Well, decacorn is the new unicorn, and refers to those companies worth $10B and more. Take a look at the CEOs behind these tech innovators, all of whom are faring pretty well themselves.

Adam Neumann, WeWork

Adam Neumann co-founded WeWork with business partner Miguel McKelvey. The two clawed their way into the office rental game in 2010 and have since turned office real estate on its ear. In its latest round of funding, WeWork raised $260M, pushing its valuation to $16.9B. Adam has a net worth of $2.4B.

Brian Chesky, Airbnb

Despite ongoing legal battles in New York and San Francisco, Airbnb continues to thrive. The home-sharing site, founded by Joe Gebbia, Nathan Blecharczyk and Brian Chesky (from left), is giving the hotel industry a run for its money. Airbnb was recently valued at $30B; CEO Brian Chesky's net worth is closing in on $3.3B.

Evan Spiegel, Snapchat

Social media platform Snapchat went live in September 2011. Co-founder and CEO Evan Spiegel launched the platform to offer users an authentic look into their friends' lives. Evan is worth $2.1B and that's likely to increase once the company proceeds with its plans to go public in Q1 2017, pushing it valuation to $25B.

Alex Karp, Palantir

Alex Karp's company has been referred to as a combination of "Big Brother and Big Data." The billionaire CEO launched the CIA-funded software company in 2004 and is making big moves, recently announcing plans to acquire data visualization startup Silk, a $3.7B company. As of last year the company was valued at $20B, with Karp's personal net worth hitting $1.6B.