A through-the-cycle model for retail lending economic capital

Problems in the US mortgage industry have shown weaknesses in the standard regulatory and economic capital approaches. Although a significant amount of discussion is occurring around how to segment portfolios or predict key variables in order to better fit the existing formulas, we believe that a re-examination of existing capital formulas with respect to credit risk is required.In this paper we develop a formula which is specifically tuned to the dynamics of retail loan portfolios and which could be employed for either regulatory capital or economic capital. The key advantages of this approach are that it is based upon a much more accurate model of retail loan defaults, does not require any new data feeds, is based upon readily available modeling frameworks, and can adapt to portfolio changes such as those observed in the US mortgage crisis.