(Bloomberg News) Twitter Inc. co-founder Jack Dorsey, 35, has joined 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.

"While a valuation of $3.2 billion is rich, and virtually unheard of for a three-year old company, Square has grown dramatically since its prior round of funding, now processing over $500 million of merchant transactions a month," PrivCo said in its report.

Closely held Rizvi, a Birmingham, Michigan-based private equity fund, will take a 6.25 percent equity stake in Square, which was co-founded by Dorsey in 2009. Square said in June two million people used its smart phone and mobile device payments processing software, double what the company said it had at the start of 2012.

Rizvi spokesman Beau Allen said in a phone call the company had no comment on the report. Rizvi Traverse owns a stake in Twitter, which Dorsey co-founded in 2006, and counts Facebook Inc., Playboy Enterprises Inc. and Summit Entertainment Group among its investments, according to its website.

Aaron Zamost, a spokesman for Square, said the company had no comment an e-mail.