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arXiv 2312.04045q-fin.MFmath.OC
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均值-方差投资组合选择博弈中的部分信息

Partial Information in a Mean-Variance Portfolio Selection Game

University of Colorado, Boulder(科罗拉多大学博尔德分校);National Central University(中央大学)

Yu-Jui Huang, Li-Hsien Sun

AI总结:

本文研究了在相对绩效标准下,多个投资者进行均值-方差投资组合选择的问题,探讨了在完全信息和部分信息情况下纳什均衡的求解方法,并指出相对绩效标准可能导致投资者财富的下行自我强化现象。

摘要:

本文考虑了多个投资者在相对绩效标准下进行均值-方差投资组合选择的问题。每个投资者不仅关注终端财富,还关注其与所有投资者终端财富平均值的比较。在人际层面,每个投资者根据其他人的策略选择交易策略,同时该策略还需在个人层面达到均衡,以解决投资者当前和未来自我之间的时间不一致性(由均值-方差目标引发)。我们寻找的纳什均衡是一个交易策略元组,其中每个投资者同时实现个人均衡。我们在完全信息的理想情况下显式推导了此类纳什均衡,并在部分信息的现实情况下半显式地推导了该均衡。部分信息下的公式包括短视交易和跨期对冲项,两者均依赖于一个额外的状态过程,该过程用于过滤真实的预期回报,其对交易的影响由退化的柯西问题捕捉。我们的结果表明,相对绩效标准可以导致投资者财富的下行自我强化——如果每位投资者同时遭受财富下降,那么每个人的财富趋势会进一步下降。数值示例显示,这种现象在完全信息下微不足道,但在部分信息下则显著。

英文摘要:

This paper considers finitely many investors who perform mean-variance portfolio selection under relative performance criteria. That is, each investor is concerned about not only her terminal wealth, but how it compares to the average terminal wealth of all investors. At the inter-personal level, each investor selects a trading strategy in response to others' strategies. This selected strategy additionally needs to yield an equilibrium intra-personally, so as to resolve time inconsistency among the investor's current and future selves (triggered by the mean-variance objective). A Nash equilibrium we look for is thus a tuple of trading strategies under which every investor achieves her intra-personal equilibrium simultaneously. We derive such a Nash equilibrium explicitly in the idealized case of full information (i.e., the dynamics of the underlying stock is perfectly known) and semi-explicitly in the realistic case of partial information (i.e., the stock evolution is observed, but the expected return of the stock is not precisely known). The formula under partial information consists of the myopic trading and intertemporal hedging terms, both of which depend on an additional state process that serves to filter the true expected return and whose influence on trading is captured by a degenerate Cauchy problem. Our results identify that relative performance criteria can induce downward self-reinforcement of investors' wealth--if every investor suffers a wealth decline simultaneously, then everyone's wealth tends to decline further. This phenomenon, as numerical examples show, is negligible under full information but pronounced under partial information.

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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