Quote from jrkob:
Okay, for those unfunded transactions, yes, you watch out for floating bodies as you say. Although generally in this case IBs will sign a CSA with the seller so that the seller is supposed to post collateral in an amount equal to the mark-to-market loss (in sort, this is a litle bit simplified).
The riskiest swap would be one that is not done under CSA, since generally in this case the protection buyer will only be collateralized by - at best - an upfront amount. Meaning that the buyer faces huge recovery risk.
For funded transactions, the whole transaction is obviously fully collateralized on day one so its essentially riskless for the protection buyer.
In my opinion, the biggest risks right now for IBs lies with the monolines, who typically do not sign CSA and do no post collateral (their AAA/Aaa rating is all they have to offer as guarantee), but even so, the big monolines, with the exception of AMBAC, have almost all their exposure to super senior tranches, eg those least risky, so IBs do not take very high risk.
If however these super senior tranches start defaulting, then the whole street goes burst.