Bacinello (2003a) employed CRR model to numerically calculate the fair value of a participating policy containing a surrender option. Bacinello assumed a constant rate of return on risk-free assets. However, this study proposes a two-dimensional CU model in a stochastic interest rate model as a means of providing a numerical method for contract pricing. The two-dimensional CU model converges rapidly and achieves similar results to Monte Carlo simulation. Two-dimensional CU models are used to analyze the importance and sensitivity of a stochastic interest rate model for the policy. Zero coupon bond volatility is an essential parameter in the surrender option, and reference portfolio volatility is important for pricing the participating option. The participating and surrender options are more valuable given upwards trending interest rates than constant or downwards trending rates.