The meaning of the Greek crisis  http://alainet.org/active/37719&lang=es

As for the rating agencies, how reliable are they? They have a pretty questionable credibility, as they were the ones who gave a triple-A rating to the subprime securities issued by Lehman Brothers, just 3 days before its bankruptcy.These same "clairvoyant" agencies are extremely powerful and do as they please on financial markets, including on those unregulated known as OTC (Over The Counter Derivatives)

or the toxic markets in which agents buy insurance against the risk of default, CDS (Credit Default Swaps). They are closely related to Anglo-Saxon banks (including Goldman Sachs and Citibank). These agencies do not work with a crystal ball, but with the abundant data provided by the issuer of the loan or the intelligence provided by the market of specific financial products.