Yep, I have been saying for years that, even if there is an issue with derivatives, total gross notional is an pretty meaningless measure of the issue. Mkt value is a better measure. If you want to use precedent and look at the Lehman default, a conservative estimate of the portfolio losses there is arnd $315mln. That, on a $9trn notional portfolio, is arnd 0.0035%.Quote from sle:
Further, the exposure of 70tn is absolute notional outstanding, whch is probably netted across counterparties in a rather benighn way.
Unfortunately, people take notional exposure as some number that actually has significance while in reality it's risk that matters. For example, 2s/10s and 10s/30s CMS spread options in the brokers market have social size of 1bn, so getting to trillion with fairly little risk is not that hard.