Abstract
To quantify the impact of business cycles on the dynamics of credit ratings, conditional migration matrices and probabilities of the corresponding macroeconomic scenarios are estimated. The approach is tested on a Standard and Poor's (S&P's) dataset that covers the period from 1991 to 2013. The difference between the conditional probabilities and their unconditional counterparts is evaluated. It is the greatest, up to 300%, for contraction periods and downgrading probabilities.