RATING BASED LÉVY LIBOR MODEL

In this paper, we consider modeling of credit risk within the Libor market models. We extend the classical definition of the default‐free forward Libor rate and develop the rating based Libor market model to cover defaultable bonds with credit ratings. As driving processes for the dynamics of the default‐free and the predefault term structure of Libor rates, time‐inhomogeneous Lévy processes are used. Credit migration is modeled by a conditional Markov chain, whose properties are preserved under different forward Libor measures. Conditions for absence of arbitrage in the model are derived and valuation formulae for some common credit derivatives in this setup are presented.     

CORRELATED DEFAULTS IN INTENSITY-BASED MODELS

This paper presents an intensity-based model of correlated defaults with application to the valuation of defaultable securities. The model assumes that the intensities of the default times are driven by common factors as well as other defaults in the system. A recursive procedure called the "total hazard construction" is used to generate default times with a broad class of correlation structures. This approach is compared to standard reduced-form models based on conditional independence as well as alternative approaches involving copula functions. Examples are given for the pricing of defaultable bonds and credit default swaps of the regular and basket type.     

A martingale representation theorem and valuation of defaultable securities

We consider a financial framework with two levels of information: the public information generated by the financial assets, and a larger flow of information that contains additional knowledge about a random time. This random time can represent many economic and financial settings, such as the default time of a firm for credit risk, and the death time of an insured for life insurance. As the random time cannot be seen before its occurrence, the progressive enlargement of filtration seems tailor‐fit to model the larger flow of information that incorporates both the public flow and the information about the random time. In this context, our interest focuses on the following challenges: (a) How to single out the various risks coming from the financial assets, the random time, and their correlations? (b) How these risks interplay and lead to the formation of any risk in the larger flow of information? It is clear that understanding how risks build‐up and interact, when one enlarges the flow of information, is vital for an efficient risk management and derivatives' evaluation in those informational markets. Our answers to these challenges are full and complete no matter what the model for the random time is and no matter how the random time is related to the public flow. In fact, we introduce “pure default” risks, and quantify and classify these risks afterward. Then we elaborate our martingale representation results, which state that any martingale in the large filtration stopped at the random time can be decomposed into orthogonal local martingales (i.e., local martingales whose product remains a local martingale). This constitutes our first principal contribution, while our second contribution consists in evaluating various defaultable securities according to the recovery policy, within our financial setting that encompasses any default model, using a martingale “basis.” Our pricing formulas explain the impact of various recovery policies on securities and determine the types of pure default risk they entail.     

P2P网络借贷市场信用风险识别

近年来,P2P网络借贷市场成为我国金融领域的重灾区,各类问题层出不穷,不仅损害了投资者利益,而且严重扰乱了我国的金融秩序,深入研究P2P网络借贷市场存在的问题具有重要现实意义。P2P网络借贷市场是信息不对称最为严重的市场之一,对借款人信用风险进行识别是P2P网络借贷的关键环节。根据信用风险定价理论,借贷利率应该充分反映违约风险,通过检验借贷利率与违约风险之间的关系可以验证借贷市场信用风险识别机制的有效性。基于“人人贷”平台公开的历史交易数据对P2P网络借贷市场的信用风险识别问题进行实证研究,结果表明:借贷利率能部分反映借款人的信用风险,但在相同的利率水平下,其他指标与违约风险也存在显著性关系,表明相同的利率未对应相同的信用风险,平台的信用风险识别机制部分有效。进一步研究表明,在缺乏成熟、易用的个人征信产品的情况下,无论借款人、P2P平台,还是投资者,对信用风险影响因素的判断与实际情况都存在一定的偏差,工作经验丰富的借款人付出了过高的借贷成本,平台在判断收入对信用风险的影响方面出现了偏差,投资者则忽视了借款人学历的价值。建议打破个人征信数据壁垒,丰富个人征信产品,保护居民信用数据安全,以保障借贷市场的持续发展。     

Robust XVA

We introduce an arbitrage‐free framework for robust valuation adjustments. An investor trades a credit default swap portfolio with a risky counterparty, and hedges credit risk by taking a position in defaultable bonds. The investor does not know the exact return rate of her counterparty's bond, but she knows it lies within an uncertainty interval. We derive both upper and lower bounds for the XVA process of the portfolio, and show that these bounds may be recovered as solutions of nonlinear ordinary differential equations. The presence of collateralization and closeout payoffs leads to important differences with respect to classical credit risk valuation. The value of the super‐replicating portfolio cannot be directly obtained by plugging one of the extremes of the uncertainty interval in the valuation equation, but rather depends on the relation between the XVA replicating portfolio and the closeout value throughout the life of the transaction. Our comparative statics analysis indicates that credit contagion has a nonlinear effect on the replication strategies and on the XVA.     

INCORPORATING RISK AND AMBIGUITY AVERSION INTO A HYBRID MODEL OF DEFAULT

It is well known that purely structural models of default cannot explain short‐term credit spreads, while purely intensity‐based models lead to completely unpredictable default events. Here we introduce a hybrid model of default, in which a firm enters a “distressed” state once its nontradable credit worthiness index hits a critical level. The distressed firm then defaults upon the next arrival of a Poisson process. To value defaultable bonds and credit default swaps (CDSs), we introduce the concept of robust indifference pricing. This paradigm incorporates both risk aversion and model uncertainty. In robust indifference pricing, the optimization problem is modified to include optimizing over a set of candidate measures, in addition to optimizing over trading strategies, subject to a measure dependent penalty. Using our model and valuation framework, we derive analytical solutions for bond yields and CDS spreads, and find that while ambiguity aversion plays a similar role to risk aversion, it also has distinct effects. In particular, ambiguity aversion allows for significant short‐term spreads.     

TIME‐CHANGED MARKOV PROCESSES IN UNIFIED CREDIT‐EQUITY MODELING

This paper develops a novel class of hybrid credit‐equity models with state‐dependent jumps, local‐stochastic volatility, and default intensity based on time changes of Markov processes with killing. We model the defaultable stock price process as a time‐changed Markov diffusion process with state‐dependent local volatility and killing rate (default intensity). When the time change is a Lévy subordinator, the stock price process exhibits jumps with state‐dependent Lévy measure. When the time change is a time integral of an activity rate process, the stock price process has local‐stochastic volatility and default intensity. When the time change process is a Lévy subordinator in turn time changed with a time integral of an activity rate process, the stock price process has state‐dependent jumps, local‐stochastic volatility, and default intensity. We develop two analytical approaches to the pricing of credit and equity derivatives in this class of models. The two approaches are based on the Laplace transform inversion and the spectral expansion approach, respectively. If the resolvent (the Laplace transform of the transition semigroup) of the Markov process and the Laplace transform of the time change are both available in closed form, the expectation operator of the time‐changed process is expressed in closed form as a single integral in the complex plane. If the payoff is square integrable, the complex integral is further reduced to a spectral expansion. To illustrate our general framework, we time change the jump‐to‐default extended constant elasticity of variance model of Carr and Linetsky (2006) and obtain a rich class of analytically tractable models with jumps, local‐stochastic volatility, and default intensity. These models can be used to jointly price equity and credit derivatives.     

The rise of dollar credit in emerging market economies and US monetary policy

This paper examines the hypothesis that the boom in dollar credit in emerging market economies (EMEs) is associated with an excessively low interest rate in the US. For this purpose, we use a multivariate correlated unobserved component model that allows for correlation between shocks to dollar credit, cross‐border interest rate gaps—measured as the difference between emerging market interest rate and the US interest rate, and dollar index both in the short run and in the long run. In addition, it also provides us a quantitative estimate of the permanent and transitory movements in dollar credit in EMEs, interest rate gaps and dollar index. The results from this model do suggest that a temporary increase in interest rate gaps and decline in the dollar index are associated with a temporary increase in the dollar credit in EMEs with a very high degree of correlation. The estimate of the cyclical component of the dollar credit in EMEs from our model captures the recent boom and bust in this market and compares favourably to alternative trend–cycle decomposition methods.     

信用衍生品CDO对金融市场稳定性的影响研究

文章主要研究欧洲信用衍生产品CDO(Collateralized Debt Obligation,担保债务凭证)的发行对金融市场稳定性的影响.文章对CDO的发行量、市场波动率及欧洲6月期无风险利率与金融市场稳定性的关系采用联合极值的方法,建立泊松计数模型,并做实证分析,结果显示:金融中介之间的联动效应会增加金融市场的系统性风险;CDO发行量仅与负的联合极值显著正相关,表明CDO发行量越大对金融稳定性冲击越大.CDO发行量与正的联合极值不相关,说明CDO对银行进行风险管理的积极作用有限.此外,信息不对称程度及无风险利率也会对金融市场的稳定性产生影响.     

A hybrid information approach to predict corporate credit risk

This study proposes a hybrid information approach to predict corporate credit risk. In contrast to the previous literature that debates which credit risk model is the best, we pool information from a diverse set of structural and reduced‐form models to produce a model combination based on credit risk prediction. Compared with each single model, the pooled strategies yield consistently lower average risk prediction errors over time. We also find that while the reduced‐form models contribute more in the pooled strategies for speculative‐grade names and longer maturities, the structural models have higher weights for shorter maturities and investment grade names.     

安徽省农村信用社贷款利率定价机制模式探索

建立健全农村信用社利率定价机制是稳步推进利率市场化改革的一项重要内容。但是,现行农村信用社利率管理模式难以适应利率市场化风险控制的要求,探索具有区域性特色的农村信用社利率定价机制模式,强化利率风险管理,对农村信用社的可持续发展具有重要意义。     

Valuing Seller‐Defaultable Options

This study analyzes seller‐defaultable options that allow option writers to have a free‐will right to default, along with some prespecified default mechanisms. We analytically and numerically examine the pricing, hedging, defaulting, and profitability of the seller‐defaultable options, considering three possible scenarios for seller default. Analyzing the essential implications of seller‐defaultable options, we show that the option price is positively correlated with the default fine, underlying asset price, and volatility. The seller‐defaultable option's Greeks appear more complicated than those of the plain vanilla options. The likelihood of sellers defaulting increases with the underlying asset price, interest rate, volatility, and maturity time. Subject to the default mechanism, the buyers’ trading involves a trade‐off between profits and costs. © 2012 Wiley Periodicals, Inc. Jrl Fut Mark 33:129–157, 2013     

Market Discipline of Canadian Banks' Letters of Credit Activities: An Empirical Examination

While the motivation and riskiness of US off-balance sheet banking activities have been studied both theoretically and empirically, no such study has been found dealing with Canadian off-balance sheet banking activities, although such activities are numerically huge, and growing larger each year. This article provides support for a market discipline hypothesis of Canadian bank letters of credit activities by employing several market measures of risk from one-factor and multi-factor models, and an implied asset volatility from the option-pricing model. Furthermore, it examines both price and quantity response of off-balance sheet activities in the Canadian banking market by employing a tobit analysis to assess the robustness of our conclusions about market discipline. The results indicate that various market measures of risk and letters of credit are negatively related. Moreover, banks with greater portfolio risk measured in terms of equity and asset risk, high leverage and interest rate risk are less likely to issue letters of credit.     

Islamic financing and bank risks: The case of Malaysia

We examine whether Islamic financing can explain three important bank risks in a country with a dual banking system: credit risk, interest‐rate risk, and liquidity risk. Using Malaysian data, we find that commercial banks with Islamic financing have significantly lower credit and liquidity risks but significantly higher interest‐rate risk than banks without Islamic financing. There is also evidence that bank size is significantly related to credit risk; the proportion of loan sales to total liabilities and bank size are significant determinants of interest‐rate risk; and off‐balance‐sheet financing, the extent of securitization, loan volatility, bank capital, and bank size are statistically significantly related to liquidity risk. © 2005 Wiley Periodicals, Inc.     

外部信用评级隐含的风险信息研究综述

外部信用评级将融资过程与信用分析过程相分离,为资金供需双方的信息缺口开辟通渠,降低投资人信息不对称的信息搜寻成本和融资企业的交易成本,提高金融管理效率和市场效率。本文对外部信用评级与违约率、回收率、转移矩阵等风险信息隐含间的关系以及不同评级机构间的信用评级差异的国际最新研究成果进行了综合评述。     

Counter‐Credit‐Risk Yield Spreads: A Puzzle in China's Corporate Bond Market

In this paper, using China's risk‐free and corporate zero yields together with aggregate credit risk measures and various control variables from 2006 to 2013, we document a puzzle of counter‐credit‐risk corporate yield spreads. We interpret this puzzle as a symptom of the immaturity of China's credit bond market, which reveals a distorted pricing mechanism latent in the fundamental of this market. We also find interesting results about relationships between corporate yield spreads and interest rates and risk premia and the stock index, and these results are somewhat attributed to this puzzle.     

DEFAULT AND SYSTEMIC RISK IN EQUILIBRIUM

We develop a finite horizon continuous time market model, where risk‐averse investors maximize utility from terminal wealth by dynamically investing in a risk‐free money market account, a stock, and a defaultable bond, whose prices are determined via equilibrium. We analyze the endogenous interaction arising between the stock and the defaultable bond via the interplay between equilibrium behavior of investors, risk preferences and cyclicality properties of the default intensity. We find that the equilibrium price of the stock experiences a jump at default, despite that the default event has no causal impact on the underlying economic fundamentals. We characterize the direction of the jump in terms of a relation between investor preferences and the cyclicality properties of the default intensity. We conduct a similar analysis for the market price of risk and for the investor wealth process, and determine how heterogeneity of preferences affects the exposure to default carried by different investors.     

基于博弈理论的供应链企业间信用风险分析

供应链企业间存在着信用风险问题,上下游企业供应商和销售商之间在赊销方面进行着相互的利益博弈。由于信息的不完全性,这种博弈是一种不完全信息博弈。通过对此博弈的分析可以深层次把握影响供应链信用风险的各种成因,降低不诚信销售商通过违约所带来的收益、提高供应商调查的概率和调查成功的概率,降低检查成本、加强供应链企业诚信教育等是治理供应链信用风险的有效措施。     

The Defaultable Lévy Term Structure: Ratings and Restructuring

We introduce the intensity-based defaultable Lévy term structure model. It generalizes the default-free Lévy term structure model by Eberlein and Raible, and the intensity-based defaultable Heath-Jarrow-Morton approach of Bielecki and Rutkowski. Furthermore, we include the concept of multiple defaults, based on Schönbucher, within this generalization.     

The Interdependence between Trade Credit and Bank Lending: Commitment in Intermediary Firm Relationships

This study investigates the interdependence between trade and bank credit among 468 Portuguese small and medium‐sized enterprises (SMEs). The results show that a single bank relationship is prevalent among Portuguese SMEs, indicating that the proprietary borrower information that banks obtain through their relationship results in an information monopoly that creates a holdup problem and leads to high interest rates. Suppliers that can control their customers' credit risk may provide additional credit and thus help alleviate concerns associated with holdup costs. Trade credit is a viable alternative to short‐term debt, especially when firms' main bank is unwilling to increase its exposure to liquidity constraints.