The social network’s shares began trading just past 11:30 am, or about two hours after Mark Zuckerberg remotely rang the Nasdaq’s opening bell from Facebook headquarters in Menlo Park (including a delay in Nasdaq being able to post the initial pricing, causing some to suggest Facebook’s ticker symbol should be TILT).

Initial trades were for around $42.05 per share, compared to the $38 per share IPO price. That puts its current market cap at approximately $90 billion, and its fully-diluted value around $117 billion.

Expectations for where it will go for the rest of today are all over the place, with many expecting a gigantic pop reminiscent of what happened last year for LinkedIn (LNKD). In general, the consensus seems to be that Facebook shares will close out the day at around $50, although such prognostications were made before learning about the actual opening trade figures.

Update: As of 11:52pm, the shares had fallen back to $38.01 per share. Perhaps we’re seeing a replay on Zynga (ZNGA), rather than on LinkedIn.

More on Facebook:

• Dan Primack: Facebook’s pre-IPO pricing history
• Dan Primack The biggest Facebook winners
• Gallery: Zuck through the years
• Dan Primack: Facebook prices at $38
• Helft & Hempel: Inside Facebook
• Ryan Bradley: What I saw in Zuckerberg’s bungalow
• Dan Primack: Stop worrying about Facebook’s insider sales
• Cyrus Sanati: Why I’m not buying Facebook
• Dan Primack: Facebook IPO date has tax implications
• Miguel Helft: The man behind the Facebook IPO