Quote in context:
"The fact that deciding on a fair value has been so tough reflects the complexity of the products as much as the state of the markets. Setting a price for derivatives that have been repeatedly repackaged, overcollateralised and subordinated is difficult in any conditions. “Four thousand pieces of a Porsche are more difficult to value than a Porsche itself and the sum of the parts does not equal the whole,” says Bill Michael of KPMG, an accountancy firm (choosing an appropriate car)."