Incremental Risk Charge Methodology

In this paper, we present a methodology for calculating IRC. First, a Merton-type model is introduced for simulating default and migration. The model is modified to incorporate concentration. The calibration is also elaborated. Second, a simple approach to determine market data, including equity, in response to default and credit migration is presented. Next, a methodology toward constant level of risk is described. The details of applying the constant level of risk assumption and aggregating different subportfolios are addressed. Finally, the empirical and numerical results are presented.