Technical paper
Testing rating accuracy
As Basel II approaches the implementation stage, regulators have identified internal ratings validation as a key challenge for banks using this approach. Here, Bernd Engelmann, Evelyn Hayden and Dirk Tasche build upon previous research showing how to use…
Op risk modelling for extremes
Part 2: Statistical methods In this second of two articles, Rodney Coleman, of Imperial College London, continues his demonstration of the uncertainty in measuring operational risk from small samples of loss data.
Why be backward?
Originally developed as a tool for calibrating smile models, so-called forward methods can also be used to price options and derive Greeks. Here, Peter Carr and Ali Hirsa apply the technique to the pricing of continuously exercisable American-style put…
Coarse-grained CDOs
While analytical models of credit portfolio risk using conditional independence have been one of the most promising areas of recent research, they often involve granularity assumptions that are violated in CDO reference portfolios. Here, Michael Pykhtin…
Dealing with discrete dividends
Over the past year, we have published several papers on the issue of options on stocks with discrete dividends. At least three distinct models are used by practitioners, involving trade-offs between accuracy and tractability. Here, Remco Bos, Alexander…
The front-month proxy hedge
The front-month proxy hedge is a correlation-based hedge that seeks to neutralise the aggregate sensitivity of a portfolio to a futures curve by converting the individual futures hedges into a single hedge with respect to only the front-month contract…
Volatile volatilities
When pricing exotic interest rate derivatives, calibration of model parameters to vanilla cap or swaption prices can be especially time-consuming, especially if stochastic volatility is incorporated into the standard Libor market models or low…
Loan portfolio value
Using a conditional independence framework, Oldrich Vasicek derives a useful limiting form for the portfolio loss distribution with a single systematic factor. He then derives a risk-neutral distribution suitable for traded portfolios, and shows how…
Weather option pricing with transaction costs
The weather derivatives market is becoming more liquid, and dynamic hedging of weather options with weather swaps is now possible, though limited by transaction costs. Here Stephen Jewson investigates the effect of such hedging on option pricing
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…
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…
A joint state-space model for spot and futures power
Portfolio-wide risk management requires a model that accounts correctly for correlations between the spot asset and various futures products. Kjetil Kåresen and Egil Husby discuss a joint multi-factor model for power spot and futures prices and show how…
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…