Don’t look for employees at these companies to break out shredders – or even break a sweat – quite yet, but the Securities and Exchange Commission might be curious about certain details related to Facebook, LinkedIn, Twitter, and Zynga.  Unconfirmed rumors indicate the SEC is looking into their privately traded stock.

Peter Lattman reported, "The agency has sent information requests to several participants in the buying and selling of stock in these four companies, according to two people with direct knowledge of the inquiry who requested anonymity because they were not authorized to speak about it."

Then Lattman continued, "It is uncertain what exactly the S.E.C. is looking into, but several securities lawyers say it could relate to understanding the number of shareholders at these companies. . . .  If they had 500 shareholders, S.E.C. rules would require them to disclose their financial results to the public."

So an investigation that actually turned up something could force Facebook, LinkedIn, Twitter, and/or Zynga to go public.  At the same time, that evidence of wrongdoing would make it much more difficult for the companies to attract private investors.

Again, though, nothing’s been confirmed.  The only organization connected to this rumor to actually go on the record is SecondMarket, and it just told Dan Primack today that the SEC hasn’t been in touch.

We’ll be sure to report any significant updates.