企业财务危机预测的贝叶斯模型研究

本文探讨商业银行如何利用贝叶斯分类技术构建企业客户财务危机预测模型。本文使用财务比率作为评价企业绩效的特征属性,并考察两个不同的贝叶斯模型在估计企业客户发生财务危机的后验概率方面的有效性。一个比较简单但有较多的假设,即朴素贝叶斯模型;另一个某种程度上更为复杂但有更少的假设,即组合属性贝叶斯模型。研究发现,与朴素贝叶斯模型相比,由于组合属性贝叶斯模型更好地反映了变量之间潜在的联合分布,因此它能在历史数据支持下估计所要求的概率并做出更精确的预测。所提出的模型可以作为辅助银行审核者做出正确而快速决策的有用工具。     

Changes of firm size distribution: The case of Korea

In this paper, the distribution and inequality of firm sizes is evaluated for the Korean firms listed on the stock markets. Using the amount of sales, total assets, capital, and the number of employees, respectively, as a proxy for firm sizes, we find that the upper tail of the Korean firm size distribution can be described by power-law distributions rather than lognormal distributions. Then, we estimate the Zipf parameters of the firm sizes and assess the changes in the magnitude of the exponents. The results show that the calculated Zipf exponents over time increased prior to the financial crisis, but decreased after the crisis. This pattern implies that the degree of inequality in Korean firm sizes had severely deepened prior to the crisis, but lessened after the crisis. Overall, the distribution of Korean firm sizes changes over time, and Zipf’s law is not universal but does hold as a special case.     

一个描述金融投资项目演化的量子力学状态方程

本文提出了一个描述金融投资项目演化的量子力学状态方程,该方程的参数比较好地模拟了金融市场的基本要素,包括投资(输入)、资产损耗(缩水)、资产增益、和收益(输出)等,方程中的量子力学算符也能够反映该项目的动力学过程与特征,所以能代表一类金融投资项目(其状态用Dirac符号表示)在市场中的演化模式.通过引入纠缠态表象得出了该方程的量子解(算符之和形式),该量子解给出了初态与终态的联系,也就给出了投资项目的动态过程.作为例子,求出单一投资项目在金融市场中的演化,不但得出了符合市场演化趋势的解,而且提出了二项-负二项纠缠态.在推导过程中,充分利用了Dirac符号和有序算符内的积分技术(IWOP).     

基于外部融资的风险厌恶零售商的订货策略研究

选取资金不足风险厌恶的零售商为研究对象,在零售商选取银行贷款的融资模式下假定市场需求是随机的,应用CVaR风险准则计算零售商的最优订货量,并与风险中性时零售商的最优订货量进行对比,得出在银行贷款融资方式下,风险厌恶的零售商的订货量小于风险中性的最优订货量,并进一步分析出现这种结果的原因.对全文得到的结论进行总结,指出文中得到的理念结果可为供应链企业提供决策的参考依据,并进一步指出未来的研究方向.     

基于组合预测的静态利率期限结构优化模型

针对单个静态利率期限结构模型在拟合收益率曲线时的不足,本文引入组合预测的方法,在绝对误差和与方差和最小准则下,分别建立了静态利率期限结构组合优化模型,并给出了模型的遗传算法求解过程。然后将上海证券交易所2004～2009年的国债每日交易数据分为样本内数据和样本外数据,对多项式样条、指数样条、NS、SV和组合优化模型进行实证比较。结果表明：无论是对于样本内数据的拟合,还是对于样本外数据的预测,组合优化模型的统计特征指标几乎都要优于其他单一模型,并且具有良好的适应性和稳健性,适用于拟合我国国债利率期限结构。     

The loss given default of a low-default portfolio with weak contagion

In this paper we study the loss given default (LGD) of a low default portfolio (LDP), assuming that there is weak credit contagion among the obligors. We characterize the credit contagion by a Sarmanov dependence structure of the risk factors that drive the obligors’ default, where the risk factors are assumed to be heavy tailed. From a new perspective of asymptotic analysis, we derive a limiting distribution for the LGD. As a consequence, an approximation for the entire distribution, in contrast to just the tail behavior, of the LGD is obtained. We show numerical examples to demonstrate the limiting distribution. We also discuss possible applications of the limiting distribution to the calculation of moments and the Value at Risk (VaR) of the LGD.     

基于SVt-EVT-Vine Copula的投资组合VaR研究

针对现有风险度量模型不能准确的模拟高维金融资产收益率风险,以上证指数、沪深300指数和股指期货指数为例,首先利用SVt和EVT对各序列的边缘分布进行建模,然后采用Vine Copula方法分析多序列之间的秩相关关系和极大似然值估计法估计参数,得到RVine,CVine和DVine三种不同树结构的分解模型,通过Monte Carlo模拟法计算出在同一边缘分布不同Vine Copula方法下和在不同边缘分布同一Vine Copula方法下单资产和投资组合的金融风险VaR.经实证检验并分析对比,VaR和返回式检验均表明SVt和EVT相结合对边缘分布有较好的拟合效果,再运用RVine描述资产间的相依结构在度量投资组合金融风险方面更准确合理.     

考虑集团化经营特征的企业财务困境风险预警研究

企业的集团化经营特征将会对财务困境风险产生重要的影响.在分析集团化经营企业财务风险特征的基础上,考虑集团内部交叉持股复杂度、关联交易程度和相互担保程度对集团化经营企业财务状况的影响,使用KMV模型计算集团化经营企业的违约距离,构建了全新的集团化经营企业财务困境预警的评价体系.并运用Logistic回归模型对集团化经营企业财务困境进行预警.实证结果表明该指标体系与模型具有可行性和有效性.     

Network theory and behavioral finance in a heterogeneous market environment

This article addresses the stock market as a complex system. The complexity of the stock market arises from the structure of the environment, agent heterogeneity, interactions among agents, and interactions with market regulators. We develop the idea of a meta‐model, which is a model of models represented in an agent‐based model that allows us to investigate this type of market complexity. The novelty of this article is the incorporation of various complexities captured by network theoretical models or induced by investment behavior. The model considers agents heterogeneous in terms of their strategies and investment behavior. Four investment strategies are included in the model: zero‐intelligence, fundamental strategy, momentum (trend followers), and adaptive trading strategy using the artificial neural network algorithm. In terms of behavior, the agents can be risk averse or loss occupied with overconfidence or conservative biases. The agents may interact with each other by sharing market sentiments through a structured scale‐free network. The market regulator controls the market through various control tools such as the risk‐free rate and taxation. Parameters are calibrated to the S&P500. The calibration is implemented using a scatter search heuristic approach. The model is validated using various stylized facts of stock return patterns such as excess kurtosis, auto‐correlation, and ARCH effect phenomena. Analysis at the macro and micro level of the market was performed by measuring the sensitivity of volatility and market capital and investigating the wealth distributions of the agents. We found that volatility is more sensitive to the model parameters than to market capital, and thus, the level of volatility does not affect market capital. In addition, the findings suggest that the efficient market hypothesis holds at the macro level but not at the micro level. © 2016 Wiley Periodicals, Inc. Complexity 21: 530–554, 2016     

Security design and firm dynamics under long‐term moral hazard

This paper addresses a moral hazard problem in which the agent's actions affect the future profits of the firm. The optimal contract can be implemented through the issuance of variable coupon debt and purchase of fixed‐coupon debt. Consequently, the resulting capital structure acts as a hedge for the firm, reducing underinvestment costs in bad states of nature and controlling overinvestment incentives in good ones. However, owing to asymmetric information between the firm's manager and investors, this hedge is only partial. The firm's investments vary with cash flows, disclosing the agent's asymmetric information to the principal. Copyright © 2016 John Wiley & Sons, Ltd.