We know that Twitter has a “truckload of money,” according to its current CEO Dick Costolo, so assuming its creators are millionaires is an easy assumption to make.

But guess what? You’re wrong! One of them, Jack Dorsey, is now a billionaire.

Dorsey is one of those people who works all the time. Seriously. He has two full-time jobs: one at Twitter (of course) and one at his other startup, Square.

According to Bloomberg, the 35-year-old is now joining the ranks of the world’s billionaires.

Dorsey’s mobile payment company, Square Inc., is in the process of closing a $200 million investment by Rizvi Traverse Management LLC, valuing the company at $3.2 billion, according to a report Wednesday by PrivCo, a New York-based research firm that specializes in private companies’ financial data.

The report, citing unnamed sources, said Dorsey will own 26 percent of Square after this round of financing closes. The stake would be worth $845 million. Coupled with his ownership in Twitter, the social media company, Dorsey is a billionaire, the report said.

So what’s next for Dorsey? Do you think he’ll look to start yet another company, or do you think this workaholic will finally slow down a little bit?

(Workaholic image from Shutterstock)