Moskovitz, 28, now runs his own company, Asana, which develops enterprise software for workspaces, and has no connection the Facebook, of Menlo Park, Calif. But filings with the U.S. Securities and Exchange Commission show he still retains 106.8 million Class B shares of the company, which can be converted to class A shares at any time.
Based on Thursday's price of $19.23, up 12 cents, Moskovitz's remaining Facebook investment is valued around $2.05 billion, about half the value of their May 17 initial public offering price.
Moskovitz was a roommate at Harvard College of Zuckerberg when they devised the concept of "The Facebook" in 2004 as a means of putting freshman class photos and bios on line.
Representatives of both Asana, in San Francisco, as well as Facebook, didn't immediately respond to requests for comment early Thursday.
So far, Asana has raised $10.2 million in venture capital from well-heeled firms Andreesen Horovitz and Benchmark Capital, as well as from early Facebook investor Peter Thiel, who last week sold 20 million shares at an average price of $20 to raise $400 million.
Former Facebook president Sean Parker, who sold 3.4 million shares for an undisclosed price before the IPO, but still holds more than 65 million shares, is another Asana investor.