论文标题
意识到崩溃风险可以改善凯利的策略在模拟的财务时间序列中
Awareness of crash risk improves Kelly strategies in simulated financial time series
论文作者
论文摘要
我们模拟了价格过程的简化版本,包括Kreuser和Sornette(2018)中提出的气泡和崩溃。价格过程被定义为几何随机步行,并结合通过与正(和负)气泡相关的单独的离散分布建模的跳跃。该模型的关键要素是假设跳跃的大小与气泡大小成正比。因此,跳跃往往会有效地将多余的气泡价格带回接近正常或基本价值(有效崩溃)。这与研究的现有过程不同,该过程假定跳跃独立于错误定价。与Kreuser and Sornette(2018)相比,本模型被简化了,因为我们忽略了随着价格高于正常价格的加速,崩溃概率发生的可能性。我们研究投资策略的行为,以最大限度地利用风险资产和无风险资产的财富预期日志(凯利标准)。我们表明,该方法的行为与凯利(Kelly)在几何布朗运动方面的行为相似,因为它长期优于其他方法,并且比古典凯利(Kelly)胜过其他方法。作为表现优于性能的主要来源,我们确定了有关崩溃的存在的知识,但有趣的是,发现只有大小而不是发生时间的知识,已经提供了重要而强大的优势。然后,我们执行错误分析,以表明该方法相对于参数的变化是可靠的。该方法对预期回报中的错误最敏感。
We simulate a simplified version of the price process including bubbles and crashes proposed in Kreuser and Sornette (2018). The price process is defined as a geometric random walk combined with jumps modelled by separate, discrete distributions associated with positive (and negative) bubbles. The key ingredient of the model is to assume that the sizes of the jumps are proportional to the bubble size. Thus, the jumps tend to efficiently bring back excess bubble prices close to a normal or fundamental value (efficient crashes). This is different from existing processes studied that assume jumps that are independent of the mispricing. The present model is simplified compared to Kreuser and Sornette (2018) in that we ignore the possibility of a change of the probability of a crash as the price accelerates above the normal price. We study the behaviour of investment strategies that maximize the expected log of wealth (Kelly criterion) for the risky asset and a risk-free asset. We show that the method behaves similarly to Kelly on Geometric Brownian Motion in that it outperforms other methods in the long-term and it beats classical Kelly. As a primary source of outperformance, we determine knowledge about the presence of crashes, but interestingly find that knowledge of only the size, and not the time of occurrence, already provides a significant and robust edge. We then perform an error analysis to show that the method is robust with respect to variations in the parameters. The method is most sensitive to errors in the expected return.