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arXiv 1908.00982q-fin.RM
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在模型不确定性下,使用经验数据计算最坏情况下的风险价值预测

calculation worst-case Value-at-Risk prediction using empirical data under model uncertainty

Wentao Hu

摘要:

模型不确定性下风险头寸的量化从外部监管和内部管理两个角度来看都是至关重要的。模型不确定性的概念,有时也称为模型模糊性。虽然我们知道模型家族,但我们不能精确地决定使用哪一个。给定集合$\mathcal{P}$,风险度量$ρ$的值在所有可能模型的集合上在一定范围内变化。这个范围内的最大值被称为最坏情况值,相应的模型被称为最坏情况。风险价值(Value-at-Risk,VaR)自提出以来,已成为一种非常流行的风险度量工具。WVaR(worst-case风险价值)自然引起了众多研究者的关注。虽然许多文献研究了WVaR,但对实证数据分析的影响仍然很少。本文提出了一种特殊的模型--不确定性市场模型,将$\mathcal{P}$简化为一个包含有限个概率分布的集合。该模型具有两层混合分布模型的结构。采用变点检测法对收益率序列进行分段,然后采用EM算法进行参数估计。最后,我们计算了四个金融市场的VaR、WVaR(worst-case风险价值)和BVaR(best-case风险价值),并分析了它们的不同表现。

英文摘要:

Quantification of risk positions under model uncertainty is of crucial importance from both viewpoints of external regulation and internal management. The concept of model uncertainty, sometimes also referred to as model ambiguity. Although we know the family of models, we cannot precisely decide which one to use. Given the set $\mathcal{P}$, the value of the risk measure $ρ$ varies in a range over the set of all possible models. The largest value in such a range is referred to as a worst-case value, and the corresponding model is called a worst scenario. Value-at-Risk(VaR) has become a very popular risk-measurement tool since it was first proposed. Naturally, WVaR(worst-case Value-at-Risk) attracts the attention of many researchers. Although many literatures investigated WVaR, the implications for empirical data analysis remain rare. In this paper, we proposed a special model uncertainty market model to simply the $\mathcal{P}$ to a set contain finite number of probability distributions. The model has the structure of the two-layer mixed distribution model. We used change point detection method to divide the returns series and then used EM algorithm to estimate the parameters. Finally, we calculated VaR, WVaR(worst-case Value-at-Risk) and BVaR(best-case Value-at-Risk) for four financial markets and then analyzed their different performance.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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