Don't forget the role of the rating agencies in the financial crisis. In the 1975 the U.S. Congress designated the Nationally Recognized Statistical Rating Organizations (NRSRO's). When Congress passed the legislation anointing the NRSRO’s it gave this limited number of organizations oligopoly status and unique competitive advantage. At the same time, Congress appointed the Securities and Exchange Commission as regulator of the NRSRO's.
Most investment advisors and portfolio managers use rating agency guidelines (ratings) to assist their evaluation of the quality and risk associated with the securities they purchase* and fiduciaries are restricted by law as to the minimum rating level from which they can select the investments they can purchase and manage. So, the rating agencies provide a seal of approval, so to speak, for the securities and companies they rate.
* In most cases, the ratings securities an investment advisor, or a portfolio manager will use are defined in a prospectus, offering circular, or by some other form of disclosure.
and Too Little, Too Late