Square CEO and Twitter chairman Jack Dorsey is on his way to becoming a billionaire.

Six years after cofounding Twitter, Jack Dorsey is close to breaching the 10-figure net worth mark.

Dorsey will likely be the latest Silicon Valley entrepreneur to become a billionaire, because his mobile payment startup, Square, is in the process of closing a round of funding that will pt its value at a rich $3.2 billion.

Square is set to receive a $200 million injection from Birmingham, Michigan-based private equity firm Rizvi Traverse, doubling the company’s last valuation, according to a report from private company research expert PrivCo.

While it had been widely reported in April that Square was seeking a funding round at a valuation of $4 billion, PrivCo’s report states that “there were signs prospective investors were pushing back on a high $4 billion valuation.” Square settled for a so-called “pre-money” valuation of $3 billion, according to PrivCo, reducing CEO Dorsey’s stake in the three-year-old company to about 26.4%. In June, it had been reported, and corroborated by a document from Alaska’s Department of Commerce, Community and Economic Development, that Dorsey’s stake in the company was 28.3%.

At Square’s post-money valuation of $3.2 billin, Dorsey’s stake in Square will be worth about $845 million. Dorsey also has a stake in Twitter, which PrivCo valls “relatively modest” and FORBES estimates as worth more than $200 million. The combination of the two equity stakes---should the reporting new funding Square be successfully completed---will make the Twitter chairman and Square CEO eligible to join the ranks of American billionaires.

A spokesperson for Square declined to comment on Dorsey’s net worth.

In his company’s report, PrivCo CEO Sam Hamadeh says he doesn’t see Square “being an independent company forever.”

“PrivCo has always felt that Square was a company being ‘built to be bough,’ and we still feel that is true, as the company would make a perfect acquisition for a major payment processor that is behind the curve on mobile payment,” Hamadeh says.

According to sources, Square’s revenues, which are derived directly from the amount of payments they process through its platform, have been rapidly growing over the last two ywar. Revenues for 2011 were at $42.5 million, and sales for 2012 are roughly expected to reach $165 million. At a $3.2 billion, Square’s latest valuation means that the company is worth more than 19 times projected revenues for 2012.

From Forbes