Credit derivatives

The Economist has another moan about credit derivatives.

Economist.com | Articles by Subject | Credit derivatives: "Of course, things can go wrong. It is possible that the pricing of ever more complicated instruments might sometimes be too much even for the ultra-brainy lot who do it, with expensive results. Tranched instruments have no clear market price, so they have to be valued with complex models. Working out whether a default in a portfolio is likely to be an isolated event, or is a harbinger of more to come, is especially tricky, not least because data on credit defaults are relatively sparse. "