Mark Zuckerberg's $2 billion day

Facebook's beaten down stock soared today, posting its biggest one-day gain since going public and boosting its CEO Mark Zuckerberg net wealth by a cool $2 billion. Shares closed up $19.13 percent to close at $23.23 after Facebook yesterday posted solid quarterly earnings and showed that it's on its way to making big money from mobile.

The rare rally came as Zuckerberg spent much of yesterday's conference call convincing Wall Street analysts that mobile is not a problem but a monstrous opportunity that he is tackling with full force.

It's only a one-day bump, of course, and the stock is still far from its May IPO price of $38 a share. But employees who have watched their holdings sink must be having a good day. As for Zuckerberg, he owns 540 million Class B shares (those are the ones that have extra voting power) and in September saidhe wouldn't sell any stock for 12 months. Even so, it's got to feel good to watch your holding jump more than $2 billion in a single day.