Efficient Risk Estimation via Nested Sequential Simulation
研究嵌套模拟中估计金融风险的计算问题，提出一种新算法，通过序贯分配内层模拟计算资源，使风险估计收敛速度优于传统均匀采样方法，对金融风险管理者有用。
We analyze the computational problem of estimating financial risk in a nested simulation. In this approach, an outer simulation is used to generate financial scenarios, and an inner simulation is used to estimate future portfolio values in each scenario. We focus on one risk measure, the probability of a large loss, and we propose a new algorithm to estimate this risk. Our algorithm sequentially allocates computational effort in the inner simulation based on marginal changes in the risk estimator in each scenario. Theoretical results are given to show that the risk estimator has a faster convergence order compared to the conventional uniform inner sampling approach. Numerical results consistent with the theory are presented. This paper was accepted by Gérard Cachon, stochastic models and simulation.