Tagged Questions

The possibility that a negative event (such as a loss) will happen.

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4
votes
2answers
413 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 ...
19
votes
4answers
6k views

What is the best way to “fix” a covariance matrix that is not positive semi-definite?

I have a sample covariance matrix of S&P 500 security returns where the smallest k-th eigenvalues are negative and quite small (reflecting noise and some high correlations in the matrix). I am ...
10
votes
2answers
775 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. ...
8
votes
1answer
665 views

How to compute modified-CVaR in the PerformanceAnalytics package?

My objective is to measure the modified-CVAR for a portfolio given its weights and matrix of security returns. Luckily the wonderful package PerformanceAnalytics has an ES() function that does just ...
6
votes
2answers
210 views

Is it better to grade hedging strategies based on the sum of absolute or squared hedging errors?

Let's say I have one strategy that has a hedging error of: 2, 2, -2, -2 Let's say I have another strategy that has a hedging error of .5, .5, 3, 3 Would it be a better idea to grade the hedging ...
5
votes
3answers
110 views

Which lags or percentiles should be run in a batch when calculating Value-at-Risk?

Are there any "standard" VaR calculations run in a batch? For example, testing a VaR calculation with a lag of 1,2, 5 or 10 days over 2 years? Same question for the percentile, 1%, 2.5%, 5% etc.
7
votes
2answers
331 views

Do you know a good article on ETF's counterparty risk analysis?

I am at the moment considering investing into ETFs, but I am looking first to understand how these products really work. Indeed, it is my understanding that ETF can vary in terms of structure, thus ...
5
votes
1answer
866 views

Value at Risk backtesting (kupiec)

I m doing my research on estimating Value at risk using different assumptions on volatility and then compare my results based on backtesting. I obtained results and just on question based on my ...
9
votes
4answers
1k views

Is the risk-free rate really limited by inflation?

In all the classic texts on equities derivatives, there is an assumption of the risk-free rate r. We can immediately dismiss the concept of a fixed rate; all interest rates are variable (and ...
9
votes
2answers
783 views

What is the relationship between risk aversion and preference for skewness and kurtosis in portfolio optimization?

Is there any relationship between the risk aversion coefficient in an individual's utility function (commonly used in portfolio optimization) and the preference for higher moments such as skewness and ...
7
votes
1answer
1k views

What is the basis risk between cash and futures government bonds?

I am currently working in a team responsible for maintaining a simple risk application for our bond desk and I am interested in knowing how to provide some sort of basic basis risk metric. Our desk ...
6
votes
5answers
673 views

Indicators and research for stress-based investment strategies

In reference to this paper: Can risk aversion indicators anticipate financial crises? and the investable UBS Risk Adjusted Dynamic Alpha Strategy: ...
15
votes
1answer
983 views

Portfolio optimization with monte carlo sampling from predictive distribution

Let's say we have a predictive distribution of expected returns for N assets. The distribution is not normal. We can interpret the dispersion in the distribution as reflection of our uncertainty (or ...
4
votes
1answer
404 views

How to model the risk of a CFD

I'm struggling to understand why the risk on an equity CFD is not the same as for the corresponding equity. The RiskMetrics FAQ mentions two ways to model a CFD, but it does not explain why this is ...
5
votes
1answer
4k views

Annualzing the log of daily returns riddle

Two popular ways to measure returns are Arithmetic returns and Log returns. Let's define arithmetic (simple period) returns as: P(t) - P(t-1) / P(t-1). Let's define log return as Ln( P(t)/P(t-1) ) or ...
8
votes
4answers
687 views

What are the risk factors in analysing strategies?

What do you think of strategies displayed on timelyportfolio.blogspot.com? I really like the fact that there is some code to reproduce the strategies, but they seem very elementary because he does ...
10
votes
3answers
1k 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} ...
4
votes
7answers
1k 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
586 views

Minimizing Correlation

Is there a quantitative method in monitoring trades to reduce the possibility of correlated trades?
4
votes
5answers
842 views

Do binary options make any sense?

Reading from "www.nadex.com" - the copy reads "Binaries are similar to traditional options but with one key difference: their final settlement value will be 0 or 100. This means your maximum risk and ...
8
votes
2answers
2k views

Equity Risk Model Using PCA

I'm trying to build a simple risk model for stocks using PCA. I've noticed that when my dimensions are larger than the number of observations (for example 1000 stocks but only 250 days of returns), ...
9
votes
3answers
616 views

better estimator of volatility for small samples

One commonly used sample estimator of volatility is the standard deviation of the log returns. It is indeed a very good estimator (unbiased, ...) when the sample is large. But I don't like it for ...
3
votes
2answers
760 views

Covariance for arbitrarily large portfolios

I am implementing a method in Java to calculate the variance, covariance, and value at risk for a portfolio, which should be flexible for use with any number of assets in a portfolio. I am struggling ...
5
votes
4answers
790 views

Do low volatility stocks outperform high volatility stocks over the long run?

A recent article from Forbes seems to indicate that low volatility stocks outperform high volatility stocks over the long run. Does anyone have any supporting or contradicting evidence to this claim? ...
2
votes
1answer
214 views

Picking from two correlated distributions

Can anyone provide a simple example of picking from two distributions, such that the two generated time series give a specified value of Pearson's correlation coefficient? I would like to do this in ...
8
votes
3answers
597 views

Price of Brent versus West Texas Intermediate

As of right now, the price of Brent Crude is $\$$111.59/bbl and the price of WTI Crude is $\$$98.36/bbl. I'm well aware that futures markets don't set the spot price for oil, but actual ...
7
votes
4answers
21k views

What are some examples of non-financial risks and contingency plans?

There are many online sources about common risk factors in investing and trading e.g. market risk, credit risk, interest rate risk. There are various factor models (Fama-French, Carhart) and risk ...
11
votes
2answers
3k views

How does left tail risk differ from right tail risk?

How does left tail risk differ from right tail risk? In what context would an analyst use these metrics?
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 ...
16
votes
2answers
588 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 ...
17
votes
2answers
679 views

How are distributions for tail risk measures estimated in practice?

Let's say you want to calculate a VaR for a portfolio of 1000 stocks. You're really only interested in the left tail, so do you use the whole set of returns to estimate mean, variance, skew, and shape ...
10
votes
1answer
306 views

What approaches are there for stress testing a portfolio?

Wikipedia lists three of them: Extreme event: hypothesize the portfolio's return given the recurrence of a historical event. Current positions and risk exposures are combined with the historical ...
31
votes
5answers
2k views

Lévy alpha-stable distribution and modelling of stock prices.

Since Mandelbrot, Fama and others have performed seminal work on the topic, it has been suspected that stock price fluctuations can be more appropriately modeled using Lévy alpha-stable distrbutions ...
18
votes
7answers
5k views

How does the “risk-neutral pricing framework” work?

I've struggled for a long time to understand this - What is this? And how does it affect you? Yes I mean risk neutral pricing - Wilmott Forums was not clear about that.
10
votes
4answers
2k views

What is a “coherent” risk measure?

What is a coherent risk measure, and why do we care? Can you give a simple example of a coherent risk measure as opposed to a non-coherent one, and the problems that a coherent measure addresses in ...
14
votes
4answers
2k views

How are risk management practices applied to ML/AI-based automated trading systems

A potential issue with automated trading systems, that are based on Machine Learning (ML) and/or Artificial Intelligence (AI), is the difficulty of assessing the risk of a trade. An ML/AI algorithm ...
22
votes
2answers
4k views

What is the difference between the methods for calculating VaR?

There are three different commonly used Value at Risk (VaR) methods: Historical method Variance-Covariance Method Monte Carlo What is the difference between these approaches, and under what ...
13
votes
2answers
685 views

Concentration risk in credit portfolio

How do you model concentration risk of credit portfolio in IRB/Basel II framework?