According to Facebook's pre-IPO filing with the Securities and Exchange Commission, Moskovitz holds nearly 134 million shares of Facebook stock, giving him a 7.6 percent stake in the company. Based on the value placed on Facebook's stock in its $1 billion cash-and-stock deal for Instagram, Moskovitz's pre-IPO net worth stands at more than $4 billion.
Like many of the richest Americans, Moskovitz has signed a pledge initiated by Bill and Melinda Gates and Warren Buffett to give away most of his money. His wife runs his philanthropic foundation, which is still getting off the ground.
For now, he said he's focused "110 percent" on Asana. To hear Moskovitz tell it, the choice of coming to the office doesn't come at the expense of some wished-for life of luxury.
"It feels very much like a default. Of course you do that," Moskovitz said. "We're fortunate not to have things that would distract us from being able to act."
Follow Marcus Wohlsen on Twitter at http://twitter.com/marcuswohlsen
Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.