Hedging bond portfolios versus infinitely many ranked factors of risk

The paper considers bond portfolios affected by both interest-rate- and default-risk. In order to guarantee a correct performance of our analysis we will hedge against an infinite number of factors. Hence we do not have to impose and do not depend on any assumption concerning the dynamic behavior of the term structure of interest rates. On the other hand, since a complete hedging is not feasible unless some ideal situations hold, we rank the factors according to the empirical evidence. Thus, we make the most important risks vanish and we minimize the effect of those kinds of risk less usual in practice

Measuring concentration risk for regulatory purposes

The measurement of concentration risk in credit portfolios is necessary for the determination of regulatory capital under Pillar 2 of Basel II as well as for managing portfolios and allocating economic capital. Existing multi-factor models that deal with concentration risk are often inconsistent with the Pillar 1 capital requirements. Therefore, we adjust these models to achieve Basel II-compliant results. Within a simulation study we test the impact of sector concentrations on several portfolios and contrast the accuracy of the different models. In this context, we also compare Value at Risk and Expected Shortfall regarding their suitability to assess concentration risk. --Concentration Risk,Pillar 2,Multi-Factor Models,Economic Capital,Simulation Study,Value at Risk,Expected Shortfall

On Partial Defaults in Portfolio Credit Risk : A Poisson Mixture Model Approach

Most credit portfolio models exclusively calculate the loss distribution for a portfolio of performing counterparts. Conservative default definitions cause considerable insecurity about the loss for a long time after the default. We present three approaches to account for defaulted counterparts in the calculation of the economic capital. Two of the approaches are based on the Poisson mixture model CreditRisk+ and derive a loss distribution for an integrated portfolio. The third method treats the portfolio of non-performing exposure separately. All three calculations are supplemented by formulae for contributions of the counterpart to the economic capital. --Portfolio credit risk,CreditRisk+,Recovery

Household Portfolios: An International Comparison

This paper presents an overview of the main findings of an international project on Household Portfolios coordinated by the authors. Contributions to the project deal with the state of the art in analytical, computational, and econometric methods of analysis of household portfolio choice, identify stylized facts and trends observed in five major countries, and discuss issues relating to the portfolios of two important population groups, namely the elderly and the rich. In this paper, we integrate the main findings of the project, compare portfolio behavior across countries, and contrast theoretical predictions to empirical findings. This allows us to identify a number of stylized facts and portfolio puzzles that future theoretical and empirical research should attempt to analyze and resolve.

Managing sovereign credit risk in bond portfolios

With the recent development of the European debt crisis, traditional index bond management has been severely called into question. We focus here on the risk issues raised by the classical market-capitalization weighting scheme. We propose an approach to properly measure sovereign credit risk in a fixed-income portfolio. For that, we assume that CDS spreads follow a SABR process and we derive a sovereign credit risk measure based on CDS spreads and duration of portfolio bonds. We then consider two alternative weighting methods which are fundamental indexation and risk-based indexation. Fundamental indexation is based on GDP indexation whereas risk-based indexation uses a risk budgeting approach based on our sovereign credit risk measure. We then compare all these methods in terms of risk, diversification and performance. We show that the risk budgeting approach is the most appropriate scheme to manage sovereign credit risk in bond portfolios and gives very appealing results with respect to active management of bond portfolios.sovereign credit risk, credit spread, convex risk measure, sabr model, CDS, bond indices, fundamental indexation, risk-based indexation, risk budgeting

Hedging bond portfolios versus infinitely many ranked factors of risk

The paper considers bond portfolios affected by both interest-rate- and default-risk. In order to guarantee a correct performance of our analysis we will hedge against an infinite number of factors. Hence we do not have to impose and do not depend on any assumption concerning the dynamic behavior of the term structure of interest rates. On the other hand, since a complete hedging is not feasible unless some ideal situations hold, we rank the factors according to the empirical evidence. Thus, we make the most important risks vanish and we minimize the effect of those kinds of risk less usual in practice.

Actuarial Applications and Estimation of Extended~CreditRisk+^+

We introduce an additive stochastic mortality model which allows joint modelling and forecasting of underlying death causes. Parameter families for mortality trends can be chosen freely. As model settings become high dimensional, Markov chain Monte Carlo (MCMC) is used for parameter estimation. We then link our proposed model to an extended version of the credit risk model CreditRisk$^+$. This allows exact risk aggregation via an efficient numerically stable Panjer recursion algorithm and provides numerous applications in credit, life insurance and annuity portfolios to derive P\&L distributions. Furthermore, the model allows exact (without Monte Carlo simulation error) calculation of risk measures and their sensitivities with respect to model parameters for P\&L distributions such as value-at-risk and expected shortfall. Numerous examples, including an application to partial internal models under Solvency II, using Austrian and Australian data are shown.Comment: 34 pages, 5 figure

The use of portfolio credit risk models in Central Banks.

This report summarises the findings of the task force. It is organised as follows. Section 2 starts with a discussion of the relevance of credit risk for central banks. It is followed by a short introduction to credit risk models, parameters and systems in Section 3, focusing on models used by members of the task force. Section 4 presents the results of the simulation exercise undertaken by the task force. The lessons from these simulations as well as other conclusions are discussed in Section 5.