When the Financial Stability Forum – a committee of central bankers and supervisors – issued recommendations on how to improve global finance in March, the voluminous tome included a line which made some credit ratings officials shudder.

The report argued that one reason for the recent turmoil was a loss of investor confidence in the ratings of complex products. It called for the rating agencies to introduce a system that gave different types of ratings to structured products, from those commonly used for, say, corporate bonds.