Credit and interest rate risk are the two most important risks faced by commercial banks in their banking book. In this paper we derive a consistent and comprehensive framework to measure the integrated impact of both risks. By taking account of the repricing characteristics of assets, liabilities and off balance sheet items, we assess the integrated impact of credit and interest rate risk on banks’ economic value and capital adequacy. We then stress test a hypothetical but realistic bank using our framework and show that it is fundamental to measure the impact of credit and interest rate risk jointly.

Banks often measure credit and interest rate risk in the banking book separately and then add the risk measures to determine economic capital. This approach misses complex interactions between the two risk types. We develop a framework where these risks are analysed jointly. Since banking book positions are generally not marked to market, our model is based on book value accounting. Our simulations show that interactions matter, and that ignoring them leads to risk overstatement. The magnitude of the errors depends on the structure of the balance sheet and on the repricing characteristics of assets and liabilities.