Credit risk tools: an overview

This document presents several Credit Risk tools which have been developed for the Credit Derivatives Risk Management. The models used in this context are suitable for the pricing, sensitivity/scenario analysis and the derivation of risk measures for plain vanilla credit default swaps (CDS), standardized and bespoke collateralized debt obligations (CDO) and, in general, for any credit risk exposed A/L portfolio.\\ In this brief work we compute the market implied probability of default (PD) from market spreads and the theoretical CDS spreads from historical default frequencies. The loss given default (LGD) probability distribution has been constructed for a large pool portfolio of credit obligations exploiting a single-factor gaussian copula with a direct convolution algorithm computed at several default correlation parameters. Theoretical CDO tranche prices have been calculated. We finally design stochastic cash-flow stream model simulations to test fair pricing, compute credit value at risk (CV@R) and to evaluate the one year total future potential exposure (FPE) and derive the value at risk (V@R) for a CDO equity tranche exposure.interest rate swap, spot rate term structure, credit default swap, probability of default, copula function, direct convolution, loss given default, collateralized debt obligation, exposure at default, stochastic cash-flow stream model, value at risk, credit value at risk, future potential exposure, Monte Carlo simulation.

Dynamic hedging of portfolio credit derivatives

We compare the performance of various hedging strategies for index collateralized debt obligation (CDO) tranches across a variety of models and hedging methods during the recent credit crisis. Our empirical analysis shows evidence for market incompleteness: a large proportion of risk in the CDO tranches appears to be unhedgeable. We also show that, unlike what is commonly assumed, dynamic models do not necessarily perform better than static models, nor do high-dimensional bottom-up models perform better than simpler top-down models. When it comes to hedging, top-down and regression-based hedging with the index provide significantly better results during the credit crisis than bottom-up hedging with single-name credit default swap (CDS) contracts. Our empirical study also reveals that while significantly large moves—“jumps”—do occur in CDS, index, and tranche spreads, these jumps do not necessarily occur on the default dates of index constituents, an observation which shows the insufficiency of some recently proposed portfolio credit risk models.hedging, credit default swaps, portfolio credit derivatives, index default swaps, collateralized debt obligations, portfolio credit risk models, default contagion, spread risk, sensitivity-based hedging, variance minimization

Systematic and Liquidity Risk in Subprime-Mortgage Backed Securities

The misevaluation of risk in securitized ?nancial products is central to understand- ing the Financial Crisis of 2007-2008. This paper characterizes the evolution of factors a¤ecting collateralized debt obligations (CDOs) based on subprime mortgages. A key feature of subprime-mortgage backed indices is that they are distinct in their vintage of issuance. Using a latent factor framework that incorporates this vintage e¤ect, we show the increasing importance of a common factor on more senior tranches during the crisis. We examine this common factor and its relationship with spreads. We estimate the e¤ects on the common factor of the ?nancial crisis.Consumer Economics: Theory, Consumer Economics: Empirical Analysis, Demographic Economics

On pricing risky loans and collateralized fund obligations

Loan spreads are analyzed for two types of loans. The first type takes losses at maturity only; the second follows the formulation of collateralized fund obligations, with losses registered over the lifetime of the contract. In both cases, the implementation requires the choice of a process for the underlying asset value and the identification of the parameters. The parameters of the process are inferred from the option volatility surface by treating equity options as compound options with equity itself being viewed as an option on the asset value with a strike set at the debt level following Merton. Using data on the stock of General Motors during 2002-3, we show that the use of spectrally negative Lévy processes is capable of delivering realistic spreads without inflating debt levels, deflating debt maturities or deviating from the estimated probability laws

Correlation, price discovery and co-movement of ABS and equity

Asset-backed securitization (ABS) has become a viable and increasingly attractive risk management and refinancing method either as a standalone form of structured finance or as securitized debt in Collateralized Debt Obligations (CDO). However, the absence of industry standardization has prevented rising investment demand from translating into market liquidity comparable to traditional fixed income instruments, in all but a few selected market segments. Particularly low financial transparency and complex security designs inhibits profound analysis of secondary market pricing and how it relates to established forms of external finance. This paper represents the first attempt to measure the intertemporal, bivariate causal relationship between matched price series of equity and ABS issued by the same entity. In a two-dimensional linear system of simultaneous equations we investigate the short-term dynamics and long-term consistency of daily secondary market data from the U.K. Sterling ABS/MBS market and exchange traded shares between 1998 and 2004 with and without the presence of cointegration. Our causality framework delivers compelling empirical support for a strong co-movement between matched price series of ABS-equity pairs, where ABS markets seem to contribute more to price discovery over the long run. Controlling for cointegration, risk-free interest and average market risk of corporate debt hardly alters our results. However, once we qualify the magnitude and direction of price discovery on various security characteristics, such as the ABS asset class, we find that ABS-equity pairs with large-scale CMBS/RMBS and credit card/student loan ABS reveal stronger lead-lag relationships and joint price dynamics than whole business ABS. JEL Classifications: G10, G12, G2

Default risk sharing between banks and markets : the contribution of collateralized debt obligations

This paper contributes to the economics of financial institutions risk management by exploring how loan securitization a.ects their default risk, their systematic risk, and their stock prices. In a typical CDO transaction a bank retains through a first loss piece a very high proportion of the expected default losses, and transfers only the extreme losses to other market participants. The size of the first loss piece is largely driven by the average default probability of the securitized assets. If the bank sells loans in a true sale transaction, it may use the proceeds to to expand its loan business, thereby incurring more systematic risk. We find an increase of the banks' betas, but no significant stock price e.ect around the announcement of a CDO issue. Our results suggest a role for supervisory requirements in stabilizing the financial system, related to transparency of tranche allocation, and to regulatory treatment of senior tranches. JEL Klassifikation: D82, G21, D74

The Influence of Collateral on Capital Requirements in the Brazilian Financial System: an approach through historical average and logistic regression on probability of default

Using data drawn from the Brazilian Central Bank Credit Information System, this paper evaluates the impact of the use of collateral on the probability of default and, consequently, on capital requirement levels in the Brazilian financial system. Literature suggests that the existence of collateral in some credit operations increases the debtor's readiness to honor its commitment and, therefore, could result in a lower probability of default. The methodology used to calculate capital requirements is based on the Basel II IRB-Foundation Approach, although the probabilities of default have been estimated by historical averages following Basel II orientation, and corroborated by a logistic regression model. The test of hypothesis about difference between collateralized and uncollateralized probabilities of default for each risk class indicates that they are statistically different. This result was obtained both from historical average probability of default as from logistic regression model.Sob condições específicas, incluindo o requerimento de capital de 11% adotado no Brasil e a Perda dado Default (ou LGD da sigla em inglês) estabelecida em 45%, este artigo também procura identificar um fator de equivalência da razão entre os requerimentos de capital para risco de crédito na Abordagem Padronizada Simplificada e aqueles calculados pela Abordagem Básica do IRB. Para a amostra utilizada, os resultados indicam que operações de não-varejo com garantia possuem uma probabilidade média de default de 2,46% e um fator de equivalência de 60%. Em contrapartida, operações não garantidas possuem uma probabilidade média de default de 6,66% e um fator de equivalência de 93%, aproximando-se bastante do fator de ponderação de 100% da Abordagem Padronizada Simplificada.

Collateral damage: Sizing and assessing the subprime CDO crisis

This paper conducts an in-depth analysis of structured finance asset-backed securities collateralized debt obligations (SF ABS CDOs), the subset of CDOs that traded on the ABS CDO desks at the major investment banks and were a major contributor to the global financial panic of August 2007. Despite their importance, we have yet to determine the exact size and composition of the SF ABS CDO market or get a good sense of the write-downs these CDOs will generate. In this paper the authors identify these SF ABS CDOs with data from Intex©, the source data and valuation software for the universe of publicly traded ABS/MBS securities and SF ABS CDOs. They estimate that 727 publicly traded SF ABS CDOs were issued between 1999 and 2007, totaling $641 billion. Once identified, they describe how and why multisector structured finance CDOs became subprime CDOs, and show why they were so susceptible to catastrophic losses. The authors then track the flows of subprime bonds into CDOs to document the enormous cross-referencing of subprime securities into CDOs. They calculate that$201 billion of the underlying collateral of these CDOs was referenced by synthetic credit default swaps (CDSs) and show how some 5,500 BBB-rated subprime bonds were placed or referenced into these CDOs some 37,000 times, transforming $64 billion of BBB subprime bonds into$140 billion of CDO assets. For the valuation exercise, the authors estimate that total write-downs on SF ABS CDOs will be $420 billion, 65 percent of original issuance balance, with over 70 percent of these losses having already been incurred. They then extend the work of Barnett-Hart (2009) to analyze the determinants of expected losses on the deals and AAA bonds and examine the performance of the dealers, collateral managers, and rating agencies. Finally, the authors discuss the implications of their findings for the “subprime CDO crisis” and discuss the many areas for future work.Debt ; Securities ; Asset-backed financing ; Banks and banking