Here's Who Will Become Filthy Rich If Square Is Really Worth $3.25 Billion

A state filing in Alaska by Square, the San Francisco-based mobile-payments startup, has given us a rare look at a private company's ownership.

Square first reported its ownership to Alaska in 2011. But it just filed a biennial report updating those figures.

The most stunning revelation: Square CEO and cofounder Jack Dorsey now owns 32 percent of the company. In 2011, Square said he owned 28.3 percent.

Square did not provide updated figures for all of its major shareholders. Most venture-capital investors have protective clauses allowing them to reinvest to maintain their proportional stakes. We're assuming those percentage stakes remained the same.

We also assumed that Square is worth $3.25 billion, the valuation assigned it in most recent financing. In a sale or an IPO, investors and founders' stakes might change based on terms that give shareholders additional shares.

Square declined to comment for this story.