Читать книгу The Sterling Bonds and Fixed Income Handbook - Mark Glowrey - Страница 40

How useful are credit ratings?

The credit ratings agencies do not have a crystal ball – a problem that is faced by anyone attempting to quantify or manage risk, including private investors. One way to measure the accuracy of their work is to study default rates.

The following table shows the results of analysis by Standard & Poor’s on bond default rates for their range of ratings for two periods:

1 the year 2005

2 an average of default rates over the period 1981-2008