Banks on a knife edge

I don't know why this hasn't been trumpeted louder: it seems as if the Facebook IPO underwriters have been left holding the baby:

Company filings after the market closed on Friday night however revealed the extent to which the banks who led Facebook’s initial public offering - in which $16bn of shares were sold to new investors - were forced to move in to the market and buy shares in order to keep the price above the $38 level. Morgan Stanley, Facebook’s lead financial adviser, ended the day with 162m shares, worth $6.16bn. Other banks including JP Morgan and Goldman Sachs also bought shares, ending the day with $3.2bn and $2.4bn holdings respectively.

Nice. So $11.7bn of shares held: if FB drops to $35 next week with investors having little appetite to buy, that's a $600mm hit to Morgan Stanley, and a similar amount spread across JPM and GS. There goes their underwriting fee, and then some.