Abstract
Since the Basel Ⅱ framework was imposed, the banking sector has kept paying much attention to the internal-ratings based (IRB) approaches for credit risk. As a result, validation of risk parameters and the underlying rating system plays an increasingly important role on the supervisory review process. Benchmarking and mapping are parts of the whole process of producing internally estimates and validation. However, most of the validation process still focuses on a static approach. But mapping should stress the need to infer the dynamic behavior of rating transitions. Thus, we propose a dynamic benchmarking model to infer default model or rating system consistency. Following the model proposed by Bardos, Foulcher and Oung, we use a state space model to do dynamic backtesting and link the dynamics of capital requirements and credit ratings. In our empirical study, the compositions of two domestic rating systems or a domestic rating system and a foreign rating system do not follow the same dynamics. As a consequent, the default models are still inconsistent.