《Executive stock option exercise with full and partial information on a
drift change point》
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作者:
Vicky Henderson, Kamil Klad\\\'ivko, Michael Monoyios, Christoph
Reisinger
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最新提交年份:
2020
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英文摘要:
We analyse the optimal exercise of an executive stock option (ESO) written on a stock whose drift parameter falls to a lower value at a change point, an exponentially distributed random time independent of the Brownian motion driving the stock. Two agents, who do not trade the stock, have differing information on the change point, and seek to optimally exercise the option by maximising its discounted payoff under the physical measure. The first agent has full information, and observes the change point. The second agent has partial information and filters the change point from price observations. This scenario is designed to mimic the positions of two employees of varying seniority, a fully informed executive and a partially informed less senior employee, each of whom receives an ESO. The partial information scenario yields a model under the observation filtration $\\widehat{\\mathbb{F}}$ in which the stock drift becomes a diffusion driven by the innovations process, an $\\widehat{\\mathbb{F}}$-Brownian motion also driving the stock under $\\widehat{\\mathbb{F}}$, and the partial information optimal stopping value function has two spatial dimensions. We rigorously characterise the free boundary PDEs for both agents, establish shape and regularity properties of the associated optimal exercise boundaries, and prove the smooth pasting property in both information scenarios, exploiting some stochastic flow ideas to do so in the partial information case. We develop finite difference algorithms to numerically solve both agents\' exercise and valuation problems and illustrate that the additional information of the fully informed agent can result in exercise patterns which exploit the information on the change point, lending credence to empirical studies which suggest that privileged information of bad news is a factor leading to early exercise of ESOs prior to poor stock price performance.
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中文摘要:
我们分析了经理股票期权(ESO)在漂移参数在一个变化点下降到一个较低值的股票上的最优行使,该变化点是一个指数分布的随机时间,与驱动股票的布朗运动无关。两个不交易股票的代理人在变化点上有不同的信息,并通过在实物衡量下最大化其贴现回报来寻求最佳行使期权。第一个代理拥有完整的信息,并观察变化点。第二个代理拥有部分信息,并从价格观察中过滤变化点。该场景旨在模拟两名资历不同的员工的职位,一名完全知情的高管和一名部分知情的级别较低的员工,每个人都收到ESO。部分信息情景产生了一个在观测过滤$\\widehat{\\mathbb{F}}下的模型,其中股票漂移成为创新过程驱动的扩散,一个$\\widehat{\\mathbb{F}}布朗运动也驱动股票在$\\widehat{\\mathbb{F}下,部分信息最优停止值函数具有两个空间维度。我们严格描述了两个代理的自由边界偏微分方程,建立了相关最佳运动边界的形状和正则性,并证明了两种信息场景中的平滑粘贴特性,利用一些随机流思想在部分信息情况下实现了这一点。我们开发了有限差分算法来数值解决代理的练习和估价问题,并说明完全知情代理的附加信息可以产生练习模式,利用变化点上的信息,实证研究表明,坏消息的特权信息是导致股票价格表现不佳之前提前行使股票期权的一个因素。
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分类信息:
一级分类:Quantitative Finance 数量金融学
二级分类:Mathematical Finance 数学金融学
分类描述:Mathematical and analytical methods of finance, including stochastic, probabilistic and functional analysis, algebraic, geometric and other methods
金融的数学和分析方法,包括随机、概率和泛函分析、代数、几何和其他方法
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