Contagion effect on bond portfolio risk measures in a hybrid credit risk model

This paper illustrates how modelling the contagion effect among assets of a given bond portfolio changes the risk perception associated to it. This empirical work is developed in a hybrid credit risk framework that incorporates recovery rate risk. Dependence structures among firms and between external shocks affecting firms together are considered. The presence of correlations among firm leverage ratios and the interrelation between default probabilities and recovery rates produces clusters of defaults with low recovery rates. This has a major impact on standard risk measures such as Value-at-Risk and conditional tail expectation. Consequently, an appropriate measurement of the contagion has a tremendous effect on the capital requirement of many financial institutions.     

自由现金流量创造力与违约风险——来自A股公司的经验证据

本文基于我国A股上市公司数据,研究了企业自由现金流量创造力与违约风险之间的关系。研究发现：(1)企业自由现金流量创造力越强,其违约风险越低。经过一系列稳健性检验后,该结论依旧成立。(2)自由现金流量创造力越强的企业往往有更低的债务规模、更高的资产收益率和更低的股票波动,因而其违约风险更低。(3)自由现金流量创造力与违约风险的负相关关系,主要存在于货币政策紧缩时期以及外部信息环境较差的企业。本文发现意味着,监管部门和投资者应重视上市公司自由现金流量创造力不足所带来的潜在债务违约风险,通过不断提高公司自由现金流量创造力,助力我国宏观经济与微观企业高质量发展。     

Modelling bonds and credit default swaps using a structural model with contagion

This paper develops a two-dimensional structural framework for valuing credit default swaps and corporate bonds in the presence of default contagion. Modelling the values of related firms as correlated geometric Brownian motions with exponential default barriers, analytical formulae are obtained for both credit default swap spreads and corporate bond yields. The credit dependence structure is influenced by both a longer-term correlation structure as well as by the possibility of default contagion. In this way, the model is able to generate a diverse range of shapes for the term structure of credit spreads using realistic values for input parameters.     

Default Risk, Asset Pricing, and Debt Control

The pricing and control of firms’ debt has become a majorissue since Merton’s (1974) seminal article. Yet Mertonas well as other recent theories presume that the asset valueof the firm is independent of the debt of the firm. However,when using debt finance, firms may have to pay a premium foran idiosyncratic default risk and may face debt constraints.We demonstrate that firm-specific debt constraints and endogenousrisk premia, based on collateralized borrowing, affect the assetvalue of the firm and, in turn, the collateral value of thefirm. In order to explore the interdependence of debt financeand asset pricing of firms, we endogenize default premia andborrowing constraints in a production-based asset pricing model.In this context then the dynamic decision problem of maximizingthe present value of the firm faces an additional constraintgiving rise to the debt-dependent firm value. We solve for theasset value of the firm with debt finance by the use of numericaldynamic programming. This allows us to solve the debt controlproblem and to compute sustainable debt as well as the firm’sdebt value.     

A set-valued Markov chain approach to credit default

We propose a novel credit default model that takes into account the impact of macroeconomic factors and intergroup contagion on the defaults of obligors. We use a set-valued Markov chain to model the default process, which includes all defaulted obligors in the group. We obtain analytic characterizations for the default process and derive pricing formulas in explicit forms for synthetic collateralized debt obligations (CDOs). Furthermore, we use market data to calibrate the model and conduct numerical studies on the tranche spreads of CDOs. We find evidence to support that systematic default risk coupled with default contagion could have the leading component of the total default risk.     

Modelling the distribution of credit losses with observable and latent factors

This paper proposes a dynamic model to estimate the credit loss distribution of the aggregate portfolio of loans granted in a banking system. We consider a sectoral approach distinguishing between corporates and households. The evolution of their default frequencies and the size of the loans portfolio are expressed as functions of macroeconomic conditions as well as unobservable credit risk factors, which capture contagion effects between sectors. In addition, we model the distributions of the Exposures at Default and the Losses Given Default. We apply our framework to the Spanish banking system, where we find that sectoral default frequencies are not only affected by economic cycles but also by a persistent latent factor. Finally, we identify the riskier sectors, perform stress tests and compare the relative risk of small and large institutions.     

Macroeconomic Conditions and the Puzzles of Credit Spreads and Capital Structure

I build a dynamic capital structure model that demonstrates how business cycle variation in expected growth rates, economic uncertainty, and risk premia influences firms' financing policies. Countercyclical fluctuations in risk prices, default probabilities, and default losses arise endogenously through firms' responses to macroeconomic conditions. These comovements generate large credit risk premia for investment grade firms, which helps address the credit spread puzzle and the under‐leverage puzzle in a unified framework. The model generates interesting dynamics for financing and defaults, including market timing in debt issuance and credit contagion. It also provides a novel procedure to estimate state‐dependent default losses.     

A Reexamination of the Tradeoff between the Future Benefit and Riskiness of R&D Increases

Many previous studies document a positive relation between research and development (R&D) and equity value. Though R&D can increase equity value by increasing firm value, it can also increase equity value at the expense of bondholder wealth through an increase in firm risk because equity is analogous to a call option on the underlying firm value. Shi [2003] tests this hypothesis by examining the relation between a firm's R&D intensity and its bond ratings and risk premiums at issuance. His results show that the net effect of R&D is negative for bondholders. We reexamine Shi's [2003] findings and in so doing make three contributions to the literature. First, we find that Shi's [2003] results are sensitive to the method of measuring R&D intensity. When we use what we argue is a better measure of R&D intensity, we find that the net effect of R&D is positive for bondholders. Second, when we use tests that Shi [2003] recognizes are even better than the ones that he uses, we find even stronger evidence of the positive effect of R&D on bondholders. Third, we examine cross‐sectional differences in the effect of R&D on debtholders. Consistent with our main finding, we document a negative relation between R&D increases and default risk. The default risk reduction is also more pronounced for firms with higher initial default scores (where the debtholders have more to gain from an R&D increase) and for firms with more bank debt (where the debtholders have greater covenant protection from the possible detriments associated with R&D increases).     

劳动保护、社保压力与企业违约风险——基于《社会保险法》实施的研究

本文利用2011年《社会保险法》实施的政策冲击所造成的准自然实验情境构建双重差分模型,考察了劳动保护对上市公司债务违约风险的影响。研究发现,劳动保护加强后,劳动密集型企业的违约风险显著提升了约1.5%。在此基础上,进一步检验了劳动保护影响企业违约风险的渠道,发现劳动保护提高了企业的经营性负债水平,并最终提高了违约风险。此外,在国有企业、融资约束水平较高、信息披露水平较低和创新水平较低的企业,劳动保护对企业违约风险的影响更加显著。本文拓展了劳动保护经济后果的研究,也为评价《社会保险法》的政策后果提供了新的经验证据。本研究可为"新冠"疫情期间政府制定政策减免企业社保支出提供参考。     

Cross-ownership as a structural explanation for over- and underestimation of default probability

Based on the work of Suzuki, we consider a generalization of Merton’s asset valuation approach in which two firms are linked by cross-ownership of equity and liabilities. Suzuki’s results then provide no arbitrage prices of firm values, which are derivatives of exogenous asset values. In contrast to the Merton model, the assumption of lognormally distributed assets does not result in lognormally distributed firm values, which also affects the corresponding probabilities of default. In a simulation study we see that, depending on the type of cross-ownership, the lognormal model can lead to both over- and underestimation of the actual probability of default of a firm under cross-ownership. In the limit, i.e. if the levels of cross-ownership tend to their maximum possible value, these findings can be shown theoretically as well. Furthermore, we consider the default probability of a firm in general, i.e. without a distributional assumption, and show that the lognormal model is often able to yield only a limited range of probabilities of default, while the actual probabilities may take any value between 0 and 1.     

Information risk and credit contagion

This paper demonstrates a positive relationship between information risk and the credit contagion effect. We use abnormal changes in the Credit Default Swaps (CDS) spreads to measure the contagion effect, and the dispersion of analyst forecasts as a proxy for information risk. We find that firms with higher information risk suffer a greater contagion effect that occurs in advance to the credit default events. This finding is robust under controls of key firm-specific characteristics and general condition of stock and credit markets.     

Systemic risk and dynamics of contagion: a duplex inter-bank network

This paper constructs a duplex banking network formed by credit relationships and information interaction via the banks’ balance sheet to model the structure of systemic risk and investigate the dynamic mechanism of contagion in terms of default and liquidity infection along with the factors that affect the extent of the contagion. We systematically explain the role that duplex banking networks play in different aspects of risk contagion. Through theoretical analysis and simulations, we conclude that asymmetric information interaction would increase the inflexibility of the system, which leads to liquidity shortage and possibly the collapse of the whole market. The weakness of systemic risk in the interior of the complex banking system can be characterized by the partial discount factor using illiquid assets in the information network. By improving the connectedness of the information network of the duplex networks, the spread of contagion can be partially slowed.     

Enterprise Risk Management Through Strategic Allocation of Capital

This article presents a conceptual framework for operationalizing strategic enterprise risk management (ERM) in a general firm. We employ a risk‐constrained optimization approach to study the capital allocation decisions under ERM. Given the decision maker's risk appetite, the problem of holistically managing enterprise‐wide hazard, financial, operational, and real project risks is treated by maximizing the expected total return on capital, while trading off risks simultaneously in Value‐at‐Risk type of constraints. This approach explicitly quantifies the concepts of risk appetite and risk prioritization in light of the firm's default and financial distress avoidance reflected in its target credit rating. Our framework also allows the firm to consider a multiperiod planning horizon so that changing business environments can be accounted for. We illustrate the implementation of the framework through a numerical example. As an initial conceptual advancement, our formulation is capable of facilitating more general ERM modeling within a consistent strategic framework, where idiosyncratic variations of firms and different modeling assumptions can be accommodated. Managerial implications are also discussed.     

Contagion models a la carte: which one to choose?

We propose a copula contagion mixture model for correlated default times. The model includes the well-known factor, copula, and contagion models as its special cases. The key advantage of such a model is that we can study the interaction of different models and their pricing impact. Specifically, we model the default times of the underlying names in a reference portfolio to follow contagion intensity processes with exponential decay coupled with a copula dependence structure. We also model the default time of the counterparty and its dependence structure with the reference portfolio. Numerical tests show that correlation and contagion have an enormous joint impact on the rates of CDO tranches and the corresponding credit value adjustments are extremely high to compensate for the wrong-way risk.     

Correlation in corporate defaults: Contagion or conditional independence?

We revisit a method used by Das et al. (2007) (DDKS) who jointly test and reject a specification of firm default intensities and the doubly stochastic assumption in intensity models of default. The method relies on a time change result for counting processes. With an almost identical set of default histories recorded by Moody’s in the period from 1982 to 2006, but using a different specification of the default intensity, we cannot reject the tests based on time change used in DDKS. We then note that the method proposed by DDKS is mainly a misspecification test in that it has very limited power in detecting violations of the doubly stochastic assumption. For example, it will not detect contagion which spreads through the explanatory variables “covariates” that determine the default intensities of individual firms. Therefore, we perform a different test using a Hawkes process alternative to see if firm-specific variables are affected by occurrences of defaults, but find no evidence of default contagion.     

信用违约风险传染建模

在信用组合中,企业的违约是相互随机依赖的。除了来自宏观经济因素的影响,即因果传染;还有一种影响来自于企业间的直接相互关系,我们称其为信用违约传染。在目前,席卷全球的次贷风暴,就是一个信用风险传染的实例。到目前为止,人们尝试了从不同角度为违约传染建模,特别是从简约模型角度出发。本文从结构模型角度出发,为信用违约传染建模。并在此模型基础上,分析其对信用衍生品定价的影响。     

The term structure of credit spreads with jump risk

Default risk analysis is important for valuing corporate bonds, swaps, and credit derivatives and plays a critical role in managing the credit risk of bank loan portfolios. This paper offers a theory to explain the observed empirical regularities on default probabilities, recovery rates, and credit spreads. It incorporates jump risk into the default process. With the jump risk, a firm can default instantaneously because of a sudden drop in its value. As a result, a credit model with the jump risk is able to match the size of credit spreads on corporate bonds and can generate various shapes of yield spread curves and marginal default rate curves, including upward-sloping, downward-sloping, flat, and hump-shaped, even if the firm is currently in a good financial standing. The model also links recovery rates to the firm value at default so that the variation in recovery rates is endogenously generated and the correlation between recovery rates and credit ratings before default reported in Altman [J. Finance 44 (1989) 909] can be justified.     

Political connection,market frictions and financial constraints: evidence from China

This paper studies the relationship between market frictions and political connections in determining financial constraints. We develop a novel index to measure the depth of political connections (PC) at the firm level and provide robust empirical evidence that firms in China actively build PC to alleviate the costs of market frictions. Specifically, we find that firms facing severe market frictions are not as financially constrained as expected. This is because these firms also possess strong PC, which alleviate the costs of market frictions. We find that market frictions can significantly affect financial constraints in Chinese firms, but only for those firms with modest levels of PC.     

公司治理影响公司财务风险吗?

绩效和公司价值往往为学术界和实务界所重视,而风险这一反映企业行为的经济后果以及企业质量的重要指标往往被忽视。这样的一个结果是,一些看似业绩很好的公司一夜之间轰然倒塌。从已有的文献看,公司治理具有改善公司业绩及公司价值的作用,同样,我们认为,公司治理应该具有风险效应,即它可能影响到公司的风险。本文以我国证券市场2002-2005年的上市公司为研究对象,研究了公司治理对企业财务风险的影响。实证结果表明,我国上市公司的公司治理结构对企业财务风险具有一定的影响。本文的研究为人们深入认识公司治理的作用以及通过合理构建公司治理结构来有效降低企业财务风险具有一定的启示意义。     

Corporate credit risk modeling and the macroeconomy

Despite a surge in the research efforts put into modeling credit and default risk during the past decade, few studies have incorporated the impact that macroeconomic conditions have on business defaults. In this paper, we estimate a duration model to explain the survival time to default for borrowers in the business loan portfolio of a major Swedish bank over the period 1994–2000. The model takes both firm-specific characteristics, such as accounting ratios and payment behaviour, loan-related information, and the prevailing macroeconomic conditions into account. The output gap, the yield curve and consumers’ expectations of future economic development have significant explanatory power for the default risk of firms. We also compare our model with a frequently used model of firm default risk that conditions only on firm-specific information. The comparison shows that while the latter model can make a reasonably accurate ranking of firms’ according to default risk, our model, by taking macro conditions into account, is also able to account for the absolute level of risk.