Technical paper/Risk management
Unsystematic credit risk
Although Basel has shifted its treatment of unsystematic credit risk from the first, capital rules pillar (where it was called the ‘granularity adjustment’) to the second, supervisory pillar of the forthcoming Accord, this issue is of great practical…
Minimising extremes
Portfolio diversification often breaks down in stressed market environments, but the co-movement of asset prices in a tail risk regime may be modelled using a coefficient of tail dependence. Here, Yannick Malevergne and Didier Sornette show how such…
Portfolio allocation to corporate bonds with correlated defaults
This article deals with the problem of optimal allocation of capital to corporate bonds in fixed income portfolios when there is the possibility ofcorrelated defaults. Under fairly general assumptions for the distribution of thetotal net assets of a set…
Fallacies about the effects of market risk management systems
This paper takes another look at allegations that risk management systems have contributed to increased volatility in financial markets, with the particular example of the summer of 1998. The paper also provides new evidence on the potential effect of…
Avoiding pro-cyclicality
David Cosandey and Urs Wolf argue that, for small to medium-sized enterprises, Basel II is pro-cyclical because of a double-counting of the risks. They present two main directions for possible capital rules that would circumvent the pro-cyclicality…
A bootstrap back-test
Back-testing
Copula vulnerability
Counterparty credit risk
Credit risk measurement of securitisation structures
Peter-Paul Hoogbruin, Harmenjan Sijtsma and Viktor Tchistiakov of ING Group Credit Risk Management present a framework for valuing securitisation tranches from an investor’s perspective.
VAR you can rely on
Analytical and simulation-based methods often appear as rivals, but many real world problems are best served by judicious combinations of both approaches. In a first of a pair of computationally themed papers, Rabi De and Tanya Tamarchenko present a…
Calculating portfolio loss
For credit portfolios, analytical methods work best for tail risk, while Monte Carlo is used to model expected loss. However, products such as CDOs require a model for the entire distribution. Sandro Merino and Mark Nyfeler meet the challenge by…
Using Bayesian networks to predict op risk
By combining qualitative and quantitative data, Bayesian networks offer the perfect solution to the compelling need for an integrated approach to operational risk management, say Martin Neil and Ed Tranham.
Risk and probability measures
Although its drawbacks are well known, VAR has become institutionalised as the market risk measure of choice among trading firms and regulators. Now there is a growing feeling that a reappraisal is overdue, exemplified here by Phelim Boyle, Tak Kuen Siu…
The maturity effect on credit risk capital
In a mark-to-market approach to credit risk capital, ratings or spread volatility has the effect of making longer-maturity loans more capital-intensive. This is incorporated in the current Basel II proposals via a maturity adjustment factor. Arguing that…
The maturity effect on credit risk capital
In a mark-to-market approach to credit risk capital, ratings or spread volatility has the effect of making longer-maturity loans more capital-intensive. This is incorporated in the current Basel II proposals via a maturity adjustment factor. Arguing that…
Testing assumptions
In calculating value-at-risk forecasts for trading portfolios, distributional assumptions are asimportant as the choice of risk factors, but it is not easy to determine the source of errorwhen rejected forecasts occur. Here, Jeremy Berkowitz develops a…
Credit risk in asset securitisations: an analytical model
How much capital should banks reserve against investments in portfolio securitisations? Asserting that recent proposals on this subject by Basel are inconsistent, Michael Pykhtin and Ashish Dev propose a new analytical model suitable for tranches of…
Honour your contribution
What is the best method for determining the risk contribution of a component in a portfolio? An exploration of the pros and cons of three important methods, showing that none dominates the others.
Credit model evaluation
With the new Basel Capital Accord scheduled for implementation in 2005, banks are having to evaluate the credit scoring models that will enable them to meet the minimum standards for Basel’s internal ratings-based (IRB) approach. Selecting an appropriate…