A coupled Markov chain approach to credit risk modeling

We propose a Markov chain model for credit rating changes. We do not use any distributional assumptions on the asset values of the rated companies but directly model the rating transitions process. The parameters of the model are estimated by a maximum likelihood approach using historical rating transitions and heuristic global optimization techniques.We benchmark the model against a GLMM model in the context of bond portfolio risk management. The proposed model yields stronger dependencies and higher risks than the GLMM model. As a result, the risk optimal portfolios are more conservative than the decisions resulting from the benchmark model.     

中国省级政府债务风险测度与分析

将财政收入分解为税收收入,土地出让收入以及其他收入。假设三类收入分别服从扩散过程,利用伊藤引理和投资组合理论,建立地方政府债务违约概率测算模型。省级政府债务违约风险的评价结果表明：税收收入和其他收入对地方政府债务违约风险的影响较大,“土地财政”的影响相对较小;偿还债务的期限越长,地方政府债务的违约风险越低;东、中、西部地区的省级地方政府债务的违约风险存在显著差别。西部地区省份的违约风险最高,东部发达地区的违约风险最低。发债试点的8个省市的违约风险普遍较低。四是如果偿还期限为5年,有29个省份的地方政府债务违约风险低于50%。     

Portfolio optimization based on GARCH-EVT-Copula forecasting models

This study uses GARCH-EVT-copula and ARMA-GARCH-EVT-copula models to perform out-of-sample forecasts and simulate one-day-ahead returns for ten stock indexes. We construct optimal portfolios based on the global minimum variance (GMV), minimum conditional value-at-risk (Min-CVaR) and certainty equivalence tangency (CET) criteria, and model the dependence structure between stock market returns by employing elliptical (Student-$t$ and Gaussian) and Archimedean (Clayton, Frank and Gumbel) copulas. We analyze the performances of 288 risk modeling portfolio strategies using out-of-sample back-testing. Our main finding is that the CET portfolio, based on ARMA-GARCH-EVT-copula forecasts, outperforms the benchmark portfolio based on historical returns. The regression analyses show that GARCH-EVT forecasting models, which use Gaussian or Student-$t$ copulas, are best at reducing the portfolio risk.     

适用于中国的信用风险缓释工具定价模型

本文提出了一个全新的基于中国市场构造的信用风险缓释工具（Credit Risk Mitigation, CRM）定价模型。与传统信用风险定价模型相比,此模型在以下两个方面做出了重要改进：将CRM购买方的信用违约风险考虑在内;在回复比率历史数据缺失的情况下,利用标的债券的交易数据及标的主体的财务信息,通过Monte Carlo模拟,估计得到标的债务的隐含回复比率。基于此模型,我们进行了情景分析和参数敏感性检验,验证了该模型在理论和实证上的可靠性。     

Implied recovery

In the absence of forward-looking models for recovery rates, market participants tend to use exogenously assumed constant recovery rates in pricing models. We develop a flexible jump-to-default model that uses observables: the stock price and stock volatility in conjunction with credit spreads to identify implied, endogenous, dynamic functions of the recovery rate and default probability. The model in this paper is parsimonious and requires the calibration of only three parameters, enabling the identification of the risk-neutral term structures of forward default probabilities and recovery rates. Empirical application of the model shows that it is consistent with stylized features of recovery rates in the literature. The model is flexible, i.e. it may be used with different state variables, alternate recovery functional forms, and calibrated to multiple debt tranches of the same issuer. The model is robust, i.e. evidences parameter stability over time, is stable to changes in inputs, and provides similar recovery term structures for different functional specifications. Given that the model is easy to understand and calibrate, it may be used to further the development of credit derivatives indexed to recovery rates, such as recovery swaps and digital default swaps, as well as provide recovery rate inputs for the implementation of Basel II.     

住房抵押贷款借款人违约风险影响因素及应对措施研究

随着房地产业的快速发展,个人住房抵押贷款已经成为商业银行的重要业务.然而,面对日趋复杂多变的市场环境,违约风险的隐患也日益显现.本文就国内外有关违约风险影响因素的研究进行了综述,指出以往研究的局限性,并结合我国实际提出了控制违约风险的建议和对策.     

Evaluating the effectiveness of Washington state repeated job search services on the employment rate of prime-age female welfare recipients

This paper uses an unbalanced panel dataset to evaluate how repeated job search services (JSS) and personal characteristics affect the employment rate of the prime-age female welfare recipients in the State of Washington. We propose a transition probability model to take into account issues of sample attrition, sample refreshment and duration dependence. We also generalize Honoré and Kyriazidou’s [Honoré, B.E., Kyriazidou, E., 2000. Panel data discrete choice models with lagged dependent variables. Econometrica 68 (4), 839–874] conditional maximum likelihood estimator to allow for the presence of individual-specific effects. A limited information test is suggested to test for selection issues in non-experimental data. The specification tests indicate that the (conditional on the set of the confounding variables considered) assumptions of no selection due to unobservables and/or no unobserved individual-specific effects are not violated. Our findings indicate that the first job search service does have positive and significant impacts on the employment rate. However, providing repeated JSS to the same client has no significant impact. Further, we find that there are significant experience-enhancing effects. These findings suggest that providing one job search services training to individuals may have a lasting impact on raising their employment rates.     

Decomposing productivity patterns in a conditional convergence framework

In this study we examine regional data on per worker GDP, disaggregated at sectoral level, by focusing our interest on the role of differences in the sectoral composition of activities, and in productivity gaps that are uniform across sectors, in explaining the catching-up process, which is realized through physical and human capital as well as technological knowledge accumulation. Our objective is to investigate how much of the interregional inequality in aggregate productivity per worker is imputable to each component. A methodology for identifying and analyzing sources of inequality from a decomposed perspective is developed in the growth framework by combining a shift-share based technique and a SUR model specification for the conditional-convergence analysis. The proposed approach is employed to analyze aggregate interregional inequality of per worker productivity levels in Italy over the period 1970–2000. With respect to the existing empirical results, our approach provides a more comprehensive and detailed examination of the contribution of each identified component in explaining the regional productivity gaps in Italy. It is argued that region-specific productivity differentials, uniform across sectors, explain a quite large share of differences in productivity per worker. However, sectoral composition plays a non negligible role, although decreasing since the end of 1980s, and very different productivity patterns emerge within geographical areas.

The optimal capital structure of the firm with stable Lévy assets returns

This article builds a new structural default model under the assumption that a firm’s assets return follows a dynamics displaying jumps of both signs. In essence, we expand the work of Hilberink and Rogers (itself an extension of the Leland and Toft framework), which deals only with negative jumps. In contrast, we make use of stable Lévy processes, and we compute the values of the firm, debt and equity under this assumption. Theoretical credit spreads can also be obtained in our framework. They prove to be consistent with the empirical credit spreads observed in financial markets.      

On the Conditional Variance of Fuzzy Random Variables

The conditional variance of random variables plays an important role for well-known variance decomposition formulas. In this paper, the conditional variance is defined for fuzzy random variables and some properties are proved, which especially generalize to the mentioned variance decomposition. Moreover, results for two special types of fuzzy random variables and an outlook for possible applications are presented.     

大股东内部资本配置的经济后果——基于国光瓷业的案例研究

本文运用案例分析法,对国光瓷业大股东的内部资本配置行为进行了研究。结果表明,系族企业构造的内部资本市场,为大股东进行关联交易、侵占中小股东的利益提供了方便。大股东通过内部资本配置,提高了自身的利益,但却损害了其控制的上市公司的利益。     

社会资本、政府干预与区域资本配置效率——来自省级工业行业数据的证据

选取2000—2012年中国大陆30个省份35个工业行业的数据为研究样本,分析社会资本和政府干预影响区域间资本配置效率的作用机制并进行实证检验后发现：较高的社会资本水平和较低的政府干预程度,有助于提高资本配置效率;社会资本与政府干预在影响资本配置效率方面存在替代关系,在政府干预比较严重的地区,社会资本对资本配置效率的影响更加显著。     

预测VaR:高阶矩可行域未必越广越好

高阶矩可行域反映了分布函数对样本高阶矩特征(非对称和尖峰、厚尾等)的适应能力,是影响VaR预测绩效的重要因素之一。本文以中、美、英、日四个股市的收益为样本,实证比较了五种高阶矩可行域各不相同的分布函数的VaR预测绩效。结果发现,可行域过于宽广(狭窄)的分布易于高(低)估样本的偏度和峰度,并高(低)估VaR,而可行域适中的广义偏斜-t和偏斜-t分布的预测绩效相对较好。此结果可为后续研究改进VaR的预测绩效提供有益借鉴。     

人力资本配置效率关键影响因素辨识

本文在对人力资本配置效率影响因素进行分类辨识的基础上,基于DEMATEL(决策试验与评价实验室)构建了能够从具有复杂关联关系的因素中识别出关键因素的决策方法。最后,通过该方法对影响因素的重要性程度进行了排序和选择,得出经济发展水平和人力资本投资是影响人力资本配置效率的关键因素。