<p>Credit risk is the risk of losses due to the failure to fulfil the obliged payment from a debtor or a counterparty. It is one of the three major components of risks that a bank faces as defined in the new Basel Accord. The credit risk literature has experienced similar rapid growth as the credit market itself. There are currently four different approaches to analyzing credit risk: structural, reduced-form, incomplete information and hybrid models. Even though there are large volumes of published research papers and books on credit risk, our understanding and management skills in this area are still very limited as evidenced by the recent crash of the subprime market. This thesis combines three working papers on credit risk modeling and aims at adding some insights and contributions to the current credit risk literature.</p><p>In the first paper, we propose to randomize the initial condition of a generalized structural model, where the solvency ratio instead of the asset value is modeled explicitly. This initial randomization assumption is motivated by the fact that market players cannot observe the solvency ratio accurately. We find that positive short spreads can be produced due to imperfect observation on the risk factor. The two models we have considered, the Randomized Merton (RM)-II and the Randomized Black-Cox (RBC)-II, both have explicit expressions for Probability of Default (PD), Loss Given Default (LGD) and Credit Spreads (CS). In the RM-II model, both PD and LGD are found to be of order of √T, as the maturity T approaches zero. It therefore provides an example that has no well-defined default intensity but still admits positive short spreads. In the RBC-II model, the positive short spread is generated through the positive default intensity of the model. Because explicit formulas are available, these two Randomized Structure (RS) models are easily implemented and calibrated to the market data. This is illustrated by a calibration exercise on Ford Motor Corp. Credit Default Swap (CDS) spread data.</p> <p>In the second paper, we introduce the inverse-CIR (iCIR) intensity model of credit risk. A multi-firm intensity-based model is constructed where negative correlations are built through the negative correlation between the Cox-Ingersoll-Ross (CIR) process and its inverse. This parsimonious setting allows us to form rich correlation structures among short spreads of different firms, while keeping nonnegative conditions for interest rates and short spreads. The bond prices are given by explicit expressions involving confluent hypogeometric functions. This model can be regarded as an extension of the Ahn & Gao (1999) one factor iCIR model on interest rates to a multi-factor framework on credit risk.</p> <p> In the third paper, we derive several forms of the equity volatility as a function of the equity value, from the structural credit risk literature. We then propose a new jump to default model by taking the equity volatility to be of the form implied by the models of Leland (1994) and Leland & Toft (1996). This model involves a process we call the Dual-Jacobi process and which has explicit formulae for its moments. Gram-Charlier expansions are then applied to approximate bond and call prices. Our model generalizes Linetsky (2006) by incorporating a local volatility which is bounded below by a positive constant. This local volatility will decrease to a positive constant for increasing stock prices, making the stock process asymptotic to Geometric Brownian Motion (GBM). In this sence, our model is more realistic than Constant Elasticity of Variance (CEV) models.</p> / Thesis / Doctor of Philosophy (PhD)

The recent U.S. subprime mortgage crisis rapidly spread throughout the world and put the global financial system under extraordinary pressure. The main implication of the recent crisis is that complex banking regulations failed to adequately identify and limit riskiness of banking systems at both domestic and international levels. In spite of a large empirical literature on the causes and remedies of the recent crisis, there remains substantial uncertainty on (i) how risk measuring models performed during crisis, (ii) how systematic factors such as house prices affected the financial system, and (iii) how effectively government policy responses resolved the financial crisis. This thesis seeks to narrow this gap in the literature by offering three empirical essays. The first essay investigates the performance of alternative parametric VaR models in forecasting riskiness of international equity portfolios. Notably, alternative univariate VaR models are compared to multivariate conditional volatility models with special focus given to conditional correlation models. Conditional correlation models include the constant conditional correlation (CCC), dynamic conditional correlation (DCC), and asymmetric DCC (ADCC) models. Various criteria are then applied for backtesting VaR models and to evaluate their one-day-ahead forecasting ability in a wide range of countries and during different global financial conditions. It is found that most VaR models have satisfactory performance with small number of violations during pre-crisis period. However, the number of violations, mean deviation of violations, and maximum deviation of violations dramatically increase during crisis period. Furthermore, portfolio models incur lower number of violations compared to univariate models while DCC and ADCC models perform better than CCC models during crisis period. From risk management perspective, most single index models fail to pass Basel criteria for internal VaR models during crisis period, whereas empirical evidence on the choice between CCC, DCC, and ADCC models is mixed. The recent crisis also raised serious concerns about factors that can systematically destabilise the whole banking system. In particular, the collapse of house prices in the United States triggered the recent subprime mortgage crisis, which was associated with a sharp increase in the number of nonperforming loans and bank failures. This in turn demonstrates the key role that house prices play in systematically undermining the whole banking system. The second essay investigates the determinants of nonperforming loans (NPL) with a special focus on house price fluctuations as a key systematic factor. Using a panel of U.S. banking institutions from 1999 to 2012, the analysis is carried out across different loan categories, different types of banks, and different bank size. It is found that house price fluctuations have a significant impact on the evolution of nonperforming loans, while the magnitude of their impact varies across loan categories, institution types, and between large and small banks. Also, the impact of house price fluctuations on nonperforming loans is more pronounced during crisis period. The last essay of this thesis investigates the effectiveness of the U.S. government strategy to combat the crisis. As a comprehensive response to the recent financial crisis, the US government created the Troubled Asset Relief Program (TARP). The Capital Purchase Program (CPP) was launched as an initial program under the TARP. The CPP was designed to purchase preferred stocks or equity warrants from viable financial institutions. Using a large panel of the U.S. commercial banks over the period 2007Q1 to 2012Q4, survival analysis is used to investigate the impact of TARP funds on the likelihood of survival in the recipient banks. It is found that larger recipient banks are more likely to avoid regulatory closure, while receiving capital assistance does not effectively help banks to avoid technical failure. This implies that governmental capital assistance serves larger banks much better than their smaller counterparts. In addition, TARP recipients are more likely to be acquired, regardless of their size and financial health. In summary, the empirical findings reveal that capital infusions do not enhance the survival likelihood of the recipient banking institutions.

Zugl.: Hagen, FernUniversity, Diss., 2006.

The aim of the thesis is to bring new insights into banks' internal credit risk estimates and their application in estimation of credit transition matrices, which are an important part of credit risk modelling with limited publicly available sources. The doctoral thesis consists of three essays that jointly analyse features of bank- sourced credit risk data and practicalities of transition matrices estimation. In the first essay, I empirically test two assumptions widely used for estimation of transition matrices: Markovian property and time homogeneity. The results indicate that internal credit risk estimates do not satisfy the two assumptions, showing evidence of both path-dependency and time heterogeneity even within a period of economic expansion. Contradicting previous findings based on data from credit rating agencies, banks tend to revert their past rating actions. The second essay analyses the extent to which transition matrices depend on the characteristics of the underlying overlapping bank-sourced credit risk datasets and the aggregation method. It outlines that the choice of aggregation approach has a substantial effect on credit risk model results. I also show that bank-sourced transition matrices are more dynamic than those produced by credit rating agencies and introduce industry-specific...

nÃo hà / O mercado bancÃrio brasileiro passou por uma sÃrie de transformaÃÃes durante a dÃcada de 1990, as quais tiveram um impacto sobre as formas de atuaÃÃo dos bancos afetando diretamente aspectos relacionados à eficiÃncia, lucratividade/rentabilidade e exposiÃÃo ao risco sistÃmico dos bancos. A partir de meados da dÃcada de 1990, com a implementaÃÃo e consolidaÃÃo do Plano Real, ocorreram mudanÃas na economia brasileira visando um cenÃrio de estabilidade econÃmica a partir da contenÃÃo da inflaÃÃo e outras polÃticas econÃmicas visando tal cenÃrio. Nessa perspectiva, apÃs esse processo de reestruturaÃÃo, observou-se um ambiente de maior concentraÃÃo do setor bancÃrio brasileiro. Esse estudo investigou a relaÃÃo entre concentraÃÃo bancÃria e spread bancÃrio, assim como um conjunto de fatores explicativos que influenciam variaÃÃes nesse spread bancÃrio. Os resultados do modelo economÃtrico divergiram da hipÃtese central levantada nesta pesquisa, de que uma estrutura mais concentrada poderia contribuir para uma reduÃÃo do spread bancÃrio geral. De acordo com esta pesquisa a concentraÃÃo poderia se mostrar negativamente relacionada com spread atravÃs de um aumento da eficiÃncia dos processos e reduÃÃes de perdas, inclusive com reduÃÃo indireta dos nÃveis de inadimplÃncia. Todavia, o que se observou atravÃs da evidÃncia economÃtrica foi a existÃncia de uma relaÃÃo positiva entre essas duas variÃveis no modelo analisado nessa pesquisa, isso pode ser observado a partir do coeficiente estimado positivo para a relaÃÃo entre o spread bancÃrio e a medida de concentraÃÃo bancÃria representada pela variÃvel MSCB1 no modelo economÃtrico. / The Brazilian banking market has undergone a series of transformations during the 1990s, which had an impact on the ways of acting banks directly affecting aspects related to efficiency, profitability / return and exposure to systemic risk of banks. From the mid-1990s, with the implementation and consolidation of the Real Plan, there were changes in the Brazilian economy for a scenario of economic stability from containing inflation and other economic policies to such a scenario. From this perspective after this restructuring process, there was a higher concentration of the Brazilian banking sector environment. This study investigated the relationship between bank concentration and banking spread as well as a set of explanatory factors that influence variations that banking spread. The results of the econometric model diverged from the central hypothesis in this research, that a more concentrated structure could contribute to a reduction in the general banking spread. According to this research the concentration could prove negatively related to spread through increased process efficiency and loss reduction including indirect reduction in default levels. But what was observed by econometric evidence was the existence of a positive relationship between these two variables in the model analyzed in this research, it can be seen from the positive estimated coefficient for the relationship between the banking spread and the measure represented bank concentration by MSCB1 variable in the econometric model.

This master thesis deals with the area of external audit of the bank in the Czech Republic. Its goal is to identify and describe the specifics making the procedures during bank's financial statements audit different from those applied by non-financial commercial subjects. The first part is focused on the general framework of the external audit. The second part describes main features of the bank identifying several risks connected with the business which have a significant influence on the approach used by the auditors. The third part describes the methodology applied by auditors during the audit of the bank.

Recent episodes of financial instability have motivated researchers as well as policy makers to intensify research on financial stability. This thesis contributes to current research and policy discussion by elaborating and empirically testing methodologies, which can be used to measure financial sector vulnerabilities and identify potential risks for financial stability. It further focuses on the link between real and the financial sector as well as possible implications of household financial distress on the aggregate economy. Together with the proposed framework we provide the survey of the current literature on these topics as well as the empirical results. We argue in favour of stress testing methodologies covering the key risks on banks' balance sheets. These frameworks can also be used for emerging markets where data availability is typically limited. It is shown that due to high volatility of credit growth in emerging economies, the static approach assuming constant balance sheet items is not very appropriate. Furthermore, the feedback effect between the financial sector and the real economy might play an important role under certain assumptions, and therefore it should be taken into account by policy makers. This effect can also emerge in the real sector itself as potential instability can...