So the real question is, did they let Facebook know this was going to happen?
If yes, then perhaps this is a media coup to frienzy up interest into the soon-to-come IPO. Perhaps they'll cancel the whole deal now, but the $50b valuation will remain in people's heads as a "good deal" that "high net worth individuals" were willing to invest at. This might help drive a traditional IPO price upwards.
If no, then perhaps this is GS's attempt to force Facebook to IPO, so they can make a few billions along the way. It's always nice to have a billion or two extra on the balance sheet, even when you're GS. Then again, it's not good business practice to screw over your clients, and somehow I don't think that's what happened.
In either case, I think the SEC should look long and hard at its rule book and see if there is any way it can bar GS from being the senior lead in the IPO. Oh wait, the SEC is made of former GS employees. Nevermind.
This perhaps? http://www.bloomberg.com/news/2010-12-10/goldman-executive-f...
The U.S. Securities and Exchange Commission won court approval to levy a $550 million penalty against Goldman Sachs Group Inc., the largest ever against a Wall Street firm, over claims the bank misled investors in collateralized debt obligations linked to subprime mortgages.
http://seekingalpha.com/article/135785-goldman-sachs-why-are...
After all, Goldman has lots of non-trading costs: buildings, salaries, software licenses, vendor payments, etc. It was actually 15.5 days of profits for Goldman, plus the $90 million Goldman lost on the deal itself.
(Goldman wasn't just a perpetrator, they were also one of the victims. If you believe the SEC, Goldman helped Paulson to defraud themselves as well as others.)
CYA