Rating agencies state that they take a rating action only when it is unlikely to bereversed shortly afterwards. Using a formal representation of the rating process, I showthat such a policy provides a good explanation for the empirical evidence: ratingchanges relatively seldom occur, they...

Using a structural model of default, I derive rating characteristics if ratings are meant tolook ‘through the cycle’ as opposed to being based on the borrowers’ current condition.The through-the-cycle method, which is employed by most rating agencies, requires aseparation of permanent and...