I know I’m out of my depth here but…
In a lot of the articles I’ve read many people are saying it’s effectively impossible to do an accurate valuation on a lot of those tanking complex financial instruments which contributed heavily to pulling the market down. This is because not only are they loaded with imploding sub-prime mortgages, but these bad mortgages are not discrete entities that can be removed since they are comprised of bits and slices of other mortgage based securities, and you can never really get to the root value.
Although unstated I assume this is because it would be absurdly complex bordering on impossible to unwind, deconstruct and extract out the bad slices leaving on the ''good" mortgages for valuation purposes.
Well… difficult yes, but impossible? With enough brainpower and computer horsepower thrown at these securities wouldn’t it be possible to unwind them, remove (analytically) the bad elements, and get a decent handle on a rational market value?