中国金融市场信用风险模型研究与应用

文章运用中国金融市场和原银行信贷登记系统数据及人民银行组织的信用评级等数据资源,在金融工程理论和技术方法创新的基础上,借鉴国际信用风险模型中违约模式代表——KMV模型原理,实证建立由判别函数和违约强度共同构成的中国金融市场违约预警模型;借鉴国际信用风险模型中盯市模式代表——CreditMetrics模型原理,使用蒙特卡罗模拟方法实证建立中国金融市场信用组合计量模型;探索这两类模型在中国信贷市场、外汇市场、货币市场和债券市场风险管理实务中的应用;并在此基础上提出了政策性建议。     

Selecting credit rating models: a cross-validation-based comparison of discriminatory power

In commercial banking, various statistical models for corporate credit rating have been theoretically promoted and applied to bank-specific credit portfolios. In this paper, we empirically compare and test the performance of a wide range of parametric and nonparametric credit rating model approaches in a statistically coherent way, based on a ‘real-world’ data set. We repetitively (k times) split a large sample of industrial firms’ default data into disjoint training and validation subsamples. For all model types, we estimate k out-of-sample discriminatory power measures, allowing us to compare the models coherently. We observe that more complex and nonparametric approaches, such as random forest, neural networks, and generalized additive models, perform best in-sample. However, comparing k out-of-sample cross-validation results, these models overfit and lose some of their predictive power. Rather than improving discriminatory power, we perceive their major contribution to be their usefulness as diagnostic tools for the selection of rating factors and the development of simpler, parametric models.

欧元体系央行内部信用评级的作用与经验借鉴

欧债危机爆发以来,随着银行贷款充当欧元区合格担保品数量的上升,央行内部信用评级（1CAS）在欧元体系信用评估框架（ECAF）中的地位得到逐步提升。文章评述了近年来ICAS在欧元体系担保框架中地位和作用的变化,并以德央行内部信用评级体系为例,重点介绍了其在维护金融稳定方面发挥的重要作用及自身运作特点,最后结合国际经验就建立健全我国央行内部信用评级系统需深入研究的问题展开思考。     

Counterparty credit risk and the credit default swap market

Counterparty credit risk has become one of the highest-profile risks facing participants in the financial markets. Despite this, relatively little is known about how counterparty credit risk is actually priced. We examine this issue using an extensive proprietary data set of contemporaneous CDS transaction prices and quotes by 14 different CDS dealers selling credit protection on the same underlying firm. This unique cross-sectional data set allows us to identify directly how dealers' credit risk affects the prices of these controversial credit derivatives. We find that counterparty credit risk is priced in the CDS market. The magnitude of the effect, however, is vanishingly small and is consistent with a market structure in which participants require collateralization of swap liabilities by counterparties.     

News sentiment and sovereign credit risk

We explore the impact of media content on sovereign credit risk. Our measure of media tone is extracted from the Thomson Reuters News Analytics database. As a proxy for sovereign credit risk we consider credit default swap (CDS) spreads, which are decomposed into their risk premium and default risk components. We find that media tone explains and predicts CDS returns and is a mixture of noise and information. Its effect on risk premium induces a temporary change in investors’ appetite for credit risk exposure, whereas its impact on the default component leads to reassessments of the fundamentals of sovereign economies.     

Rollover risk and credit risk under time-varying margin

For a firm financed by a mixture of collateralized (short-term) debt and uncollateralized (long-term) debt, we show that fluctuations in margin requirements, reflecting funding liquidity shocks, lead to increasing the firm’s default risk and credit spreads. The severity with which a firm is hit by increasing margin requirements highly depends on both its financing structure and debt maturity structure. Our results imply that an additional premium should be added when evaluating debt in order to account for rollover risks, especially for short-matured bonds. In terms of policy implications, our results strongly indicate that regulators should intervene fast to curtail margins in crisis periods and maintain a reasonably low margin level in order to effectively prevent creditors’ run on debt.     

Seeking causality between liquidity risk and credit risk: TED-OIS spreads and CDS indexes

Since the Global Financial Crisis, credit risk and its management have become one of the most appealing topics in finance literature. In this study, we investigate the interaction of credit risk and liquidity risk through the TED and the OIS spreads and various credit default swap indexes from the CDX and the iTraxx family (CDXIG, CDXHY, ITEEU, and ITEXO). The empirical analysis is conducted through the Kapetanios unit root test, the EGARCH model, the Bootstrap Toda-Yamamoto modified Wald test and the asymmetric causality analysis. The results of symmetric and asymmetric causality methods reveal that liquidity risk appears to play an important role in credit risk, and in most cases, the TED and the OIS spreads dominate the CDS indexes. It can, thus, be concluded that the TED and the OIS spreads are superior to the CDS indexes as an early warning indicator in the credit market.     

On cox processes and credit risky securities

A framework is presented for modeling defaultable securities and credit derivatives which allows for dependence between market risk factors and credit risk. The framework reduces the technical issues of modeling credit risk to the same issues faced when modeling the ordinary term structure of interest rates. It is shown how to generalize a model of Jarrow, Lando and Turnbull (1997) to allow for stochastic transition intensities between rating categories and into default. This generalization can handle contracts with payments explicitly linked to ratings. It is also shown how to obtain a term structure model for all different rating categories simultaneously and how to obtain an affine-like structure. An implementation is given in a simple one factor model in which the affine structure gives closed form solutions.     

Reliability rating and reflective questioning: a case study of extended review on Australia's risk assessment of Bt cotton

The governance of emerging technologies is frequently constructed around risk assessment processes. However, when risk assessment as a decision‐making tool is applied to controversial fields such as genetic modification, stem cell research and nano‐scaled science and technology, inherent uncertainties and conflicting social values arise to challenge the adequacy of traditional approaches. In this paper, I propose a framework through which risk assessments may be exposed to a process of ‘extended review’, incorporating both natural and social science quality criteria and modes of reflection. I call this framework ‘Reliability Rating and Reflective Questioning’. The framework is developed through a detailed case study review of a particular risk assessment document. The case study risk assessment reviewed in this paper is that performed by an Australian governmental authority on the impact of genetically modified ‘Bt’ cotton on non‐target organisms. Through highlighting errors, misrepresentations, assumptions and embedded value judgements within the risk assessment document, I argue that the framework of ‘Reliability Rating and Reflective Questioning’ can serve as a useful tool for gauging and improving the quality of risk assessment, especially when used as a decision‐making tool for emerging technologies with high levels of uncertainty and strongly conflicting values.     

Evaluating the sovereign and household credit risk in Singapore: A contingent claims approach

This study evaluates the credit risk of the household and government (sovereign) sectors in Singapore using the contingent claims approach (CCA). The CCA model estimates the default probability of both sectors based on the market value of the assets and liabilities of the sectors. Compared to the traditional credit rating system, this model is able to provide numerical estimates of the exposures and default probabilities. We find that from the year 2000 to 2013, variations in the credit risk measures correspond to the economic growth of Singapore. In addition, we suggest that the main factor affecting the credit risks in the government and household sectors in Singapore is the volatility of the assets held by both sectors, given that the asset-to-distress barrier ratios are relatively stable over the past 14 years for both sectors.     

Exploring the components of credit risk in credit default swaps

In this paper, we test the influence of various fundamental variables on the pricing of credit default swaps. The theoretical determinants that are important for pricing credit default swaps include the risk-free rate, industry sector, credit rating, and liquidity factors. We suggest a linear regression model containing these different variables, especially focusing on liquidity factors. Unlike bond spreads which have been shown to be inversely related to liquidity (i.e., the greater the liquidity, the lower the spread), there is no a priori reason that the credit default swap spread should exhibit the same relationship. This is due to the economic characteristics of a credit default swap compared to a bond. Our empirical result shows that all the fundamental variables investigated have a significant effect on the credit default swap spread. Moreover, our findings suggest that credit default swaps that trade with greater liquidity have a wider credit default swap spread.     

基于KMV模型的中国短期融资券信用风险评级研究

针对短期融资券主体信用评级未能完全准确地反映出短期融资券信用风险的问题,本文引入信用风险计量的KMV模型,运用Matlab软件计算出短期融资券的违约距离,按照违约距离的大小通过聚类分析将样本划分为六组。在此基础上,以信用利差表示投资者对短期融资券信用风险的认可,将各组信用利差与其违约距离对应起来,对各组的信用利差进行方差分析,结果显示各组之间的差异非常显著,表明分组状况比较理想,按违约距离判断短期融资券的信用风险是合适的,实现了对短期融资券的信用风险评级。     

Tournament incentives and firm credit risk: Evidence from credit default swap referenced firms

In this paper, we evaluate the impact of managerial tournament incentives on firm credit risk in credit default swap (CDS) referenced firms. We find that intra‐firm tournament incentives are negatively related to credit risk. Our results suggest that tournament incentives reduce credit risk by alleviating the potential for underinvestment when managers are concerned about exacting empty creditors. Further, we find that tournament incentives decrease credit risk when internal governance is strong or product market competition is intense. Taken together, our results suggest that creditors perceive senior manager tournament incentives (SMTI) as a critical determinant of a firm's credit risk, particularly in settings where managerial risk aversion is high.     

On the calibration of structural credit spread models

Empirical findings are mixed about the performance of structural models for term structure of credit spreads. It is commonly believed that all structural models have equally poor performance after calibration. However, proper calibration is not a trivial issue, especially for highly structural models. This paper proposes a more accurate procedure for calibrating two models: Leland–Toft (J Finance 51:987–1019, 1996) and Collin-Dufresne and Goldstein (J Finance 56:2177–2208, 2001). Using rating-based bond data, we find that the Leland–Toft model has significantly greater explanatory power for credit spreads across rating categories than previously reported. We provide theoretical explanations for these findings, and further extend our empirical analysis to include 286 individual senior bonds. Our findings help clarify the controversies over the performance of structural models in general and that of the Leland–Toft model in particular. In addition, we offer a rigorous procedure that can be used for calibrating other structural models more effectively.      

发展信用衍生产品 完善风险分担机制

完善信用风险分担机制,发展信用衍生产品,对增强我国商业银行经营的稳健性和促进直接融资市场发展部具有积极意义。当前我国发展信用衍生产品的基础性条件已基本具备,应逐步建立和完善市场的信用风险分担机制,更好地满足市场对于信用风险分散和转移的需求。     

Sovereign risk assessment and agency credit ratings

Sovereign ratings are gaining importance as more governments with greater default risk borrow in international bond markets. However, while the ratings have proved useful to governments seeking market access, the difficulty of assessing sovereign risk has led to agency disagreements and public controversy over specific rating assignments. Recognising this difficulty, the financial markets have shown some scepticism toward sovereign ratings when pricing issues.     

论无船承运人的信用风险及其规避方法

无船承运业务经营者,又名无船承运人(NVOCC),是国际货运代理经营者之一。无船承运人具有承运人和托运人双重身份,这使得其在整个操作流程中,包括合同的签订、单证的制作、费用的收付等方面都存在信用风险。明确自身的信用风险,研究规避风险的方法对规范无船承运人的操作,对降低无船承运人的经营成本具有重要意义。目前业界对无船承运人信用风险的研究还较少,本文试从无船承运人的角度来论述自身面对的信用风险及探讨其在业务流程中规避风险的方法。     

On a multivariate Markov chain model for credit risk measurement

In this paper, we use credibility theory to estimate credit transition matrices in a multivariate Markov chain model for credit rating. A transition matrix is estimated by a linear combination of the prior estimate of the transition matrix and the empirical transition matrix. These estimates can be easily computed by solving a set of linear programming (LP) problems. The estimation procedure can be implemented easily on Excel spreadsheets without requiring much computational effort and time. The number of parameters is O(s² m² ), where s is the dimension of the categorical time series for credit ratings and m is the number of possible credit ratings for a security. Numerical evaluations of credit risk measures based on our model are presented.     

Green credit policy and corporate cash holdings: Evidence from China

In 2012, China implemented a green credit policy (GCP) that restricts bank credits to heavily polluting firms. Using a difference-in-differences research design, we find that polluting firms increased their cash reserves by 9.5% after the GCP's issuance relative to non-polluting firms. We also document that the GCP significantly reduces firms' access to bank finance but increases the value of cash. Cross-sectional analysis shows that the increase in cash holdings is more significant for firms with greater financial constraints, firms with more investment opportunities, and high-tech companies. Overall, our findings are consistent with a constraint explanation: when external financing is restricted, firms retain more cash to meet future investment needs.