Economic and regulatory capital allocation for revolving retail exposures

We present two internal capital allocation models and compare the capital ratios they generate with those prescribed by the latest revision of Basel’s New Capital Accord proposal for advanced retail portfolios, which allows for explicit future margin income recognition. Given a test portfolio of credit card exposures that we assemble, we find that Basel’s ratios are closer to those generated by our models for low credit risk segments. We attribute the discrepancies to the different ways Basel and our models account for future margin income, to Basel’s assumptions about asset correlations and to one model taking macroeconomic conditions into account.