Interest rate model comparisons for participating products under Solvency II

Under the Solvency II regulatory framework it is essential for life insurers to have an adequate interest rate model. In this paper, we investigate whether the choice of the interest rate model has an impact on the valuation of the best estimate of the liabilities. We use three well-known interest rate models; the CIR++-model, the G2++-model and the Libor Market model. Our numerical results show that for low to medium durations of the liabilities and a relatively low proportion of credit bonds in the asset portfolio, the three interest rate models produce quite similar values for the best estimate liabilities. However, for large durations of the liabilities, or a large bond proportion, or both, the differences can be quite large. There is no easy answer to the question of which model should be used in cases where the choice of interest rate model has a significant impact. Based on the study described in this paper, our advice is to use the G2++-model, which seems to represent an appropriate trade-off between accuracy and complexity.