论文标题
统计危险和预期短缺的统计学习
Statistical Learning of Value-at-Risk and Expected Shortfall
论文作者
论文摘要
我们提出了两步方法的非质子收敛分析,以学习有条件的价值风险(VAR)和使用Rademacher界限的条件预期短缺(ES),并在非参数设置中,允许对财务损失进行重尾。我们的VAR方法扩展到了一次学习的问题,该问题与不同的分位数相对应。这导致基于神经网络分位数和最小二乘回归的有效学习方案。引入了后验蒙特卡洛手术,以估计地面真相和ES的距离。学生模型和金融案例研究中的数值实验可以说明这一点,其中目的是学习动态的初始保证金。
We propose a non-asymptotic convergence analysis of a two-step approach to learn a conditional value-at-risk (VaR) and a conditional expected shortfall (ES) using Rademacher bounds, in a non-parametric setup allowing for heavy-tails on the financial loss. Our approach for the VaR is extended to the problem of learning at once multiple VaRs corresponding to different quantile levels. This results in efficient learning schemes based on neural network quantile and least-squares regressions. An a posteriori Monte Carlo procedure is introduced to estimate distances to the ground-truth VaR and ES. This is illustrated by numerical experiments in a Student-$t$ toy model and a financial case study where the objective is to learn a dynamic initial margin.