Excerpts from The Big Short: Inside the Doomsday Machine by Michael Lewis, from Chapter three, "How Can a Guy Who Can't Speak English Lie?"
[I]n February 2006 ... an investor who went from the stock market to the bond market was like a small, furry creature raised on an island without predators removed to a pit full of pythons. It was possible to get ripped off by the big Wall Street firms in the stock market, but you really had to work at it. The entire market traded on screens, so you always had a clear view of the price of the stock of any given company. The stock market was not only tranparent but heavily policed. You wouldn't expect a Wall Street trader to share with you his every negative thought about public companies, but you could expect he wouldn't work very hard to sucker you with outright lies, or blatantly use inside information to trade against you, mainly becauser there was at least a chance he'd be caught if he did. The presence of millions of small investors had politicized the stock market. It had been legislated and regulated to at least seem fair.
The bond market, because it consisted mainly of big institutional investors, experienced no similarly populist political pressure. Even as it came to dwarf the stock market, the bond market eluded serious reulation. Bond salesmen could say and do anything without fear that they'd be reported to some authority. bond traders could exploit inside information without worrying that they would be caught. Bond technicians could dream up ever more complicated securities without worrying too much about government regulation--one reason why so many derivatives had been derived, one way or another, from bonds. The bigger, more liquid end of the bond market--the market for U.S. Treasury bonds, for example--traded on screens, but in many cases the only way to determine if the price some bond trader had given you was even close to fair was to call around and hope to find some other bond trader making a market in that particular obscure security. The opacity and complexity of the bond market was, for big Wall Street firms, a huge advantage. The bond market customer lived in perpetual fear of what he didn't know. If Wall Street bond departments were increasingly the source of Wall Street profits, it was in part because of this: In the bond market it was still possible to make huge sums of money from the fear, and the ignorance, of customers.