Re-Mapping Credit Ratings

  • Eisl, A. (Ko-Autor*in)
  • Hermann Elendner (Ko-Autor*in)
  • Manuel Lingo (Ko-Autor*in)

Aktivität: VortragWissenschaftlicher Vortrag (Science-to-Science)


Rating agencies report ordinal ratings in discrete classes. We question the market's implicit assumption that agencies define their classes on identical scales. To this end, we develop a non-parametric method to estimate the relation of rating scales for pairs of raters. This scale relation identifies for every rating class of one rater the extent to which it corresponds to any rating class of another, and hence enables a rating-class specific re-mapping of one agency's ratings to another's scale. Our method is based purely on ordinal co-ratings to obviate error-prone estimation of PDs and disputable assumptions involved, and exploits structure in the joint estimation of all rating classes' relations from a pair of raters.
We find evidence against the hypothesis of identical scales for the three major rating agencies Fitch, Moody's and Standard & Poor's, provide the relations of their rating classes and illustrate the importance of correcting for scale relations in benchmarking.
Zeitraum11 Mai 201113 Mai 2011
EreignistitelAssociation Française de Finance 2011 Spring Conference
VeranstaltungstypKeine Angaben