Mixed copula model with stochastic correlation for CDO pricing

This paper deals with the problem of pricing credit derivatives portfolio—CDO. The article assumes that the systematic factor and idiosyncratic factors subject to the fat-tailed mixed G-VG distribution instead of the traditional Gaussian distribution in the framework of factor model. Thus, the G-VG copula model is established. Stochastic correlation is also incorporated to account for the correlation skew problem. The semi-analytical expressions for conditional default probability, cumulative loss distribution function and expected tranche loss are explicitly derived in the G-VG copula models under large homogeneous portfolio approximation. Thus the CDO price can be determined. The numerical analysis is carried out and the properties of the new models with those of the traditional models are compared. Results show that new models not only provide a closer fit to the market quotes, but also bring more flexibility into the dependence structure.     

担保债权凭证之评价——多因子模型和KMV模型之探讨

探讨担保债权凭证商品之评价，包含缩减式模型及结构式模型两种研究方法；前者以多因子相关性模型，而後者以KMV模型为方法探讨之主轴。多因子相关性模型中资产的违约分配函数分别假设为指数、韦伯及Burr分配；再分别结合Gauss Copula或t5 Copula函数，估计商品的信用价差。实证分析以台湾“玉山银行债券资产证券化特殊目的信托2005—1受益证券”为例。实证研究结果发现，指数分配之信用价差估计值偏大，Burr分配估计值最小；t5 Copula函数之信用价差估计值都较Gauss Copula函数之估计值大。此外，将数据作适当调整後应用KMV模型之信用价差估计值比多因子相关性模型之估计值大。     

A Structural Analysis of Credit Risk With Risky Collateral: A Methodology for Haircut Determination

Although many credit risk pricing models exist in the academic literature, very little attention has been paid to the impact of risky collateral on credit risk. It is nonetheless well known that practitioners often mitigate credit risk with collateral, using so–called haircuts for collateral level determination. The presence of collateral has a complex effect that can not be analysed simply with existing models. We analyse the value of credit risk when there is collateral in a range of different situations, including dual–default in a simple setting, stochastic collateral, stochastic bond collateral with stochastic interest rates, continuous and discrete marking–to–market and margin calls. The models confirm many practical intuitions, such as the impact on the haircut level required of the risks of the collateral asset and of the underlying asset to the forward as well as the impact of their correlation. Moreover, the model supports the intuition that the frequency of marking–to–market and collateral are substitutes. The models also stress the possibly unexpected magnitude of these factors. More importantly, they give actual solutions to determining the value of the credit risk depending on the haircut chosen and the frequency of marking–to–markets, results not presented before in the literature. The models are also a good basis to understand the portfolio effect of collateral management. Finally, they illustrate how differences in prices may arise from pure differences of credit risk management, as illustrated here in the case of futures and forwards.
(J.E.L.: G13).     

Credit risk in general equilibrium

This paper contributes to the literature on default in general equilibrium. Borrowing and lending takes place via a clearing house (bank) that monitors agents and enforces contracts. Our model develops a concept of bankruptcy equilibrium that is a direct generalization of the standard general equilibrium model with financial markets. Borrowers may default in equilibrium and returns on loans are determined endogenously. Restricted to a special form of mean variance preferences, we derive a version of the capital asset pricing model with bankruptcy. In this case, we can characterize equilibrium prices and allocations and discuss implications for credit risk modeling.     

基于Poisson跳跃的信用价差期权定价

信用价差是用以向投资者补偿参照资产违约风险的、高于无风险利率的利差。信用价差期权作为风险控制的重要手段之一,其定价也日益得到人们的关注。现有文献几乎是单纯地利用几何布朗运动来刻画资产的价格变化过程从而对信用价差期权进行定价。而在实际中会出现某些不寻常的事件导致资产价格出现不间断的跳跃现象,普通的定价方法对这种现象的解释力度不够。因此本文引入Poisson跳跃来描述信用价差变化过程中的异常情况,更好地解释当遇到金融危机等情况时资产价值的跳跃现象。由于Longstaff和Schwartz的模型引入了随机利率,可以给出定价公式的封闭解析解的优点,本文在此模型上进行进行研究,将刻画信用价差动态过程的O-U过程与Poisson跳跃结合,利用伊藤公式进行推导并引入了利率的平方根过程,得到了欧式信用价差期权的定价公式,更好地考虑了资产价格的跳跃情况。     

Credit risk – Return puzzle: Evidence from India

Although asset pricing theories predict a positive relation between risk and returns, empirical findings on credit risk-return relationship are mixed. And, observed negative relation between the two in this regard is referred to as credit risk-return puzzle. Using credit rating as a measure of credit risk, we have investigated into the existence of this puzzle in India during July 2011 to March 2019. We have used information for the companies listed on the National Stock Exchange for this purpose. Our results validate the presence of this puzzle in the Indian stock market. Moreover, credit risk is observed to be a systematic risk, which has not been captured in the traditional asset pricing models. We have also observed partial evidence favoring both behavioural and rational pricing explanations—the two widely acknowledged explanations in the literature behind this puzzle. On our further query in this connection, we have not seen any significant change in the puzzle due to the recent enactment of the Insolvency and Bankruptcy Code.     

Uniform testing and portfolio strategies for single and multifactor asset pricing models in the Pacific Basin markets

We test and implement portfolio strategies for three major asset pricing models, under uniform diagnostic measures using the PACAP data set containing all current listing and de-listing of firms for the local stock exchange in several Pacific Basin countries. Compared to the often used MSCI database that include only a subset of the (large) firms in the local markets, the more complete coverage of our database allows for more robust testing of current multifactor asset pricing models since the possible effects of additional factors such as size and book to market may not show up correctly using less comprehensive data sets. Our data set also provides a natural packet of nonUS data for addressing the issue of whether the results of recent asset pricing research are sample specific. Our overall results provide multi-country (sample nonspecific) support for the additional asset pricing risk factors of the Fama-French three-factor model but not for the momentum factor of the Carhart model. We additionally find that the size risk factor is more prominent than value risk factor in the Pacific Basin markets. Finally, we find strong evidence that portfolio strategies implemented to capture value and size effects are profitable in the Pacific Basin stock markets.     

Basic Insights in Pricing Basket Credit Derivatives

Basket credit derivatives are those financial contracts whose pay–out depends on the credit events ('failure to pay', 'default', etc.) characterizing a portfolio of bonds or loans over a determined time horizon.
We have two main categories of basket credit derivatives. The first is characterized by a pay–out depending on the temporal ranking of the credit events: first–to–default, second–to–default, etc. The second is characterized by a pay–out depending on the percentiles of the portfolio's loss distribution induced by the credit events. The latter is often embedded in securitizations of portfolios of bonds or loans, i.e. CDO.
This paper proposes some basic insights in the pricing of these particularly complex credit derivatives. Whenever possible, we will try to find an analytical approximation to the exact pricing formula, if a closed form solution is not available.
(J.E.L.: G13).     

A capital adequacy buffer model

We develop a new capital adequacy buffer model (CABM) that is sensitive to dynamic economic circumstances. The model, which measures additional bank capital required to compensate for fluctuating credit risk, is a novel combination of the Merton structural model, which measures distance to default and the timeless capital asset pricing model (CAPM), which measures additional returns to compensate for additional share price risk. We apply the model to a portfolio of mid-cap loan assets over a 10-year period that includes pre-GFC (global financial crisis), GFC and post-GFC. An analysis of actual defaults over this period shows the model to be far more accurate in determining the capital adequacy levels needed to counter credit risk than an unresponsive ratings model such as the Basel standardized approach.     

基于供应商管理库存信用风险的供应链违约风险控制

受宏观经济因素的影响,市场风险和违约风险是密切相关的。而VMI作为一种在供应链相邻两级,其成功运作最重要的一个关键点,便是建立信用风险度量,以销售商违约为例,利用信用违约互换模型规避供应链违约风险,供应商和销售商更易达成交易。     

Financial market integration: Theory and empirical results

In this article, we introduce a new theoretical international asset pricing model which accounts for partial financial market segmentation. We show that if some investors do not hold all international assets because of implicit and/or explicit segmentation factors, the world market portfolio is not efficient and the classic ICAPM must be augmented by a new factor reflecting the local risk undiversifiable internationally. We test this model empirically for a sample of emerging markets. Our findings show that the degree of market integration is time-varying and that the premium associated with the domestic risk factors is the most important component of the total risk premium. However, our results also show that most of the emerging markets we study have become more integrated in the end of our sample period as a result of liberalization and reforms.     

银行信贷配给与中小企业贷款——一个内生化抵押品和企业规模的理论模型

本文在吸收其他文献合理成分的基础上 ,通过考虑贷款抵押品的信号甄别机制和银行审查成本对贷款额的影响 ,将借款企业的资产规模、风险类型与抵押品价值相联系 ,构建了内生化抵押品和企业规模的均衡信贷配给模型。根据该模型 ,在信贷配给中被剔除的主要是资产规模小于银行所要求的临界抵押品价值的中小企业和部分高风险企业。本文的理论模型对于更好地理解市场经济及转型经济条件下的中小企业融资难问题提供了启示。     

宏观经济状态对资产定价因子的影响

为刻画资产定价因子随宏观经济状态时变性,本文通过经济增长和通货膨胀两个指标定义经济状态,建立宏观经济状态下的条件资产定价模型。研究发现在中国资本市场上此模型能够显著改进CAPM模型的效力,其定价效力甚至优于多因子模型。进一步研究表明,宏观经济通过两个维度影响资产价格：第一,多数资产在衰退时期对市场风险更敏感,其代表市场因子的贝塔系数大于复苏与过热阶段;第二,小市值公司的贝塔系数均值及波动性大于大公司,在经济衰退时承担更高的风险收益。     

Sovereign Default Risk and Recovery Rates: What Government Bond Markets Expect for Greece

Bond market data on sovereign bond yields is used to estimate sovereign default risk and the amount of the expected “hair‐cut” for Greece between 2008 and 2011. Using a structural pricing model that relies on compound option theory short‐term and long‐term default probabilities and their dependencies can be inferred. Thereby bond yield spreads for different maturities are integrated. In addition, a reduced form model is applied to infer the recovery rate expected by bond market participants. The paper shows that sovereign default risk and recovery rate dynamics reflect events that are important for Greece's repayment capacity.     

Counterparty effects on capital structure decision in incomplete market

This paper builds a static contingent-claim model that allows for examining the optimal capital structure with the joint arguments of counterparty default risk and market incompleteness. A first-passage-time model with jump default barrier is adopted to capture the counterparty effects on the pricing of defaultable claims. Following the framework of Jarrow and Yu (2001), the jump in primary firm's bankruptcy barrier is designed as the loss on capital resulted from secondary firm's bankruptcy. The relevance of market incompleteness in the context of claim-pricing is considered using “good-deal asset price bound” method by Cochrane and Saa-Requejo (2000). We show that the effects of counterparty's default clearly diminish the uses of debt, which indirectly explains the so-called under-leveraged puzzle. We further find that counterparty effects on capital structure are sensitive to market incompleteness and firm's characteristics, such as tax rate and bankruptcy cost rate.     

The Role of Market Sentiment in Asset Allocations and Stock Returns

Abstract

The authors investigate the role of mutual fund flows in incorporating market sentiment into asset prices. They show that retail investors adjust their investments among mutual fund categories in response to changes in market sentiment. Consistent with sentiment-induced price pressure through fund flows, they further find that firms favored by mutual funds, such as large-cap, dividend payers, and firms with high institutional ownership are sensitive to market sentiment. The authors construct a pricing factor representing sentiment risk and find that the sentiment factor is significant in standard asset pricing models and robust to various sorting procedure.     

Modelling the dependence structures of Australian iTraxx CDS index

In contrast to market expectations, the correlation between credit default swap (CDS) spreads and their respective stock prices in Australia was found to be positive. The global financial crisis (GFC) affected the nonlinear association between the two asset classes with firms experiencing financial distress and stock prices plummeting. CDSs issuers reacted to such exogenous shocks by increasing their risk premiums on their spreads, reflecting the increased inherent risk. By splitting the data into pre- and post-GFC contexts and by employing the use of Archimedean copulas, we observe a negative co-movement in the post-GFC period. This finding is robust to several equity indices. Overall, such result is critical for investors engaging in arbitrageur activities.     

Pricing Loans Using Default Probabilities

This paper examines the pricing of loans using the term structure of the probability of default over the life of the loan. We describe two methodologies for pricing loans. The first methodology uses the term structure of credit spreads to price a loan, after adjusting for the difference in recovery rates between bonds and loans. In loan origination, it is common practice to estimate the probability of default for a loan over a specified time horizon and the loss given default. The second methodology shows how to incorporate this information into the arbitrage free pricing of a loan. We also show how to derive an estimate of the credit spread due to liquidity risk. For both methodologies, we show how to calculate a break–even credit spread, taking into account the fee structure of a loan and the costs associated with the term structure of marginal economic capital. The break–even spread is the minimum spread for the loan to be EVA neutral in a multi–period setting.
(J.E.L.: G12, G33).     

中国银行业构建现代信用风险管理模式的思考

针对信用风险的复杂特征,按照比较完善的市场风险管理模型方法可以构建现代信用风险管理模型。同时,在信息系统和内部风险评级逐步完善、信用衍生工具广泛使用的前提下,可以引入现代资产组合管理理论的思想、方法与技术,实施信用风险管理的资产组合管理方法,进而实现现代信用风险管理。重点研究现代信用风险管理的一般模式,并在此模式下,探讨中国实际背景下银行业的战略选择问题,指出完善信息管理信息系统和内部评级体系以及进一步研究信用衍生工具等金融创新的具体思路。     

Economic effects of positive credit information sharing: the case of Korea

In many countries, in addition to negative credit information such as loan default and arrears, positive credit information is also exchanged on a voluntary and reciprocal basis. Employing optimal credit decision models of profit maximizing banks, and utilizing a unique dataset of 2?million consumer loan obligors in Korea, we investigate the economic effects of sharing positive credit information in addition to negative credit information already exchanged. We find that the discriminatory power of the credit scoring model improves significantly. We proceed to investigate the economic effects of the information gap in a competitive credit market by assuming two representative banks that differ only in the level of credit information sharing. The bank that utilizes negative information only suffers from deterioration of the borrower pool and reduced profit, as high credit risk borrowers are more concentrated on this bank due to underpricing of risks. Our finding suggests that banks have incentives to voluntarily participate in the positive information sharing mechanism, since even a small difference in discriminatory power stemming from the information gap may lead to a significant fall in profitability as the distribution of borrower quality changes endogenously due to adverse selection problems.