Consistent Projection of the Balance Sheet : A Holistic Approach to Modelling Interest Rate Risk in the Banking Book

Abstract: When modelling risk in the banking book, a simple capital level approach can fail to capture the interactions between different risk measures or risk classes since they are modelled separately. In this thesis we propose a model for projecting the book value of a run-off balance sheet portfolio of fixed and variable rate loans, while also calculating net interest income, economic value of equity, capital requirement and capital cost within the same model. Using adjoint algorithmic differentiation, we also retrieve the sensitivities of each measure and the balance sheet towards a term structure of zero rates, for the lifetime of the portfolio. The model is an attempt at a holistic approach to modelling interest rate risk in the banking book, and its design allows for extensions to other financial risk classes such as credit risk and liquidity risk.