Interesting that the article mixes up Enron, Worldcom and the securitisation of US home loans. Enron and Worldcom were undone by false accounting practices and IMHO it would have been hard for rating agencies to identify these. Both were big companies where you would expect appropriate corporate governance and accounting policies/procedures. Executive of both companies were rightly sent to gaol.
In relation to securitisation, the rating agencies got it wrong big time. How you can take BBB tranches from different parts of the US, put them together and call them AAA because of diversification defies belief. Of course there is significant correlation of housing markets in a downturn.
