Piergiorgio Alessandri and Mathias Drehmann
Working Paper No. 388, Bank of England
An economic capital model integrating credit and interest rate risk in the banking book
Banks often measure credit and interest rate risk separately and then add the two risk measures to determine their overall economic capital. This approach misses complex interactions between the two risks. We develop a framework where credit and interest rate risks are analysed jointly. We focus on a traditional banking book where all positions are held to maturity and subject to book value accounting. Our simulations show that interactions between risks matter, and that their implications depend on the structure of the balance sheet and on the repricing characteristics of assets and liabilities. The analysis suggests that a joint analysis of risks can deliver substantially different results relative to a piece-wise approach: risk integration is challenging but feasible and worthwhile.