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9
votes
2answers
682 views

Links to the risk model methodologies of the major providers?

There is quite a bit of art in constructing an equity risk model. This paper summarizes some of the key decisions: choice of factors, horizon matching, cross-sectional vs. time-series method, and ...
10
votes
1answer
436 views

What weights should be used when adjusting a correlation matrix to be positive definite?

I have a correlation matrix $A$ for an equity market that is not positive definite. Higham (2002) proposes the Alternating Projections Method, minimising the weighted Frobenius norm $||A-X||_W$ where ...
10
votes
1answer
533 views

Has any research used Bayesian networks to estimate risk factor betas?

Is there any published research on estimating the beta of a security with respect to one or more risk factors via Bayesian networks? I'd like to see if this is a promising angle of research.
12
votes
2answers
1k views

Cleansing covariance matrices via Random matrix theory

I am exploring de-noising and cleansing of covariance matrices via Random Matrix Theory. RMT is a competitor to shrinkage methods of covariance estimation. There are various methods expressed usually ...
5
votes
7answers
41k views

How to calculate unsystematic risk?

We know that there are 2 types of risk which are systematic and unsystematic risk. Systematic risk can be estimate through the calculation of β in CAPM formula. But how can we estimate the ...
4
votes
2answers
444 views

Choice of prior as a shrinkage target in portfolio construction?

There's various research showing how priors such as the minimum variance portfolio turn out to be a surprisingly effective shrinkage target in portfolio construction. The sell point of these priors ...
11
votes
2answers
1k views

When should you build your own equity risk model?

Commercial risk models (e.g., Barra, Axioma, Barclays, Northfield) have evolved to a very high level of sophistication. However, all of these models attempt to solve a very broad set of problems. ...
3
votes
1answer
416 views

What research exists regarding implementation of reverse stress testing?

I need to implement a reverse stress testing model (definition here) I have searched around and cannot find anything substantial on the topic. Does anyone know of any good papers/references ...
10
votes
3answers
2k views

Is Conditional Value-at-Risk (CVaR) coherent?

When the risk is defined by a discrete random variable, is CVaR a coherent risk measure? I stick to the following definition of CVaR: $$ CVaR_\alpha(R) = \min_v \quad \left\{ v + \frac{1}{1-\alpha} ...
3
votes
1answer
523 views

Basel II modelling vs Solvency II modelling?

How do the two modelling frameworks compare? I spent some time developing PD LGD and EAD models for banking portfolios... But I never did insurance modelling project which I suspect is based on ...
5
votes
7answers
2k views

Recommendation for a book on CVA/Credit Risk and PD/LGD/EAD modeling?

I need suggestions for some good books on the following topics: Credit Value Adjustment (CVA) / Credit Risk Probability of Default / Loss-Given-Default / Exposure-At-Default modeling Any pointers ...
8
votes
2answers
2k views

Cluster analysis vs PCA for risk models?

I built risk models using cluster analysis in a previous life. Years ago I learned about principal component analysis and I've often wondered whether that would have been more appropriate. What are ...
6
votes
4answers
1k views

What does it mean to modify the factor loadings of a credit risk model?

I came across an example where a well-known weakness of a credit risk model was dealt with by augmenting some of the existing risk factors via increased factor loadings. This made the the model more ...
17
votes
2answers
676 views

How do macro funds manage risk and model asset returns? Do they use factor models?

Some of the largest funds in the world are entirely macro-based: Soros, Brevan Howard, Bridgewater. They trade across asset classes, and seemingly with very concentrated allocations. What type of risk ...