Bond indexes are often distorted because they prioritize the most indebted issuers rather than the most successful ones, which can expose passive investors to unnecessary credit risk.

“the reason that these companies became larger exposures in bond indexes is they were borrowing and borrowing and borrowing more money. And you know if you look at what happened at different periods you'll find that you know it doesn't always happen this way but if you look at GM and Ford as examples”