Questions tagged [var]

Value at Risk, a widely used risk measure of the risk of loss on a specific portfolio of financial assets.

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552 views

Computing Value at Risk for portfolio in R

I know how to compute VaR with long positions using PerformanceAnalytics. What about a portfolio consisting in two equities A and B, 100 USD long positions in each, and 2 stock options for the same ...
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3k views

VaR model Unconditional Coverage Tests: Is this extension of Kupiec POF test correct?

Background: Kupiec P. in 1995, published paper "Techniques for Verifying the Accuracy of Risk Management Models" on Journal of Derivatives, v3, P73-84, it's a Unconditional Coverage Tests designe for ...
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700 views

VaR backtesting with overlapping time intervals

Of course the issue here is dependence: can it be removed or accounted for (in independence tests too, which of course would be troublesome)? There's a lot of literature on regression in this setting, ...
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165 views

VAR FPCA analysis paper replication

I've been trying to replicate the following publication: CONSISTENT FUNCTIONAL PCA FOR FINANCIAL TIME-SERIES, Sebastian Jaimungal, Eddie K. H. Ng, 2007 but I havent been able to get the same results ...
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43 views

Joint Distribution of Correlated Variables with Markov Switching

I am modeling a portfolio of correlated assets whose lack of liquidity can be reasonably described by a Markov-switching model. That is, not only is movement size among assets correlated, but so is ...
3
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52 views

Expected Shortfall for ARMA-GARCH Model

I need to find an analytical solution for the 99% confidence expected shortfall (CVaR) for a long position of 100 dollars at time $t$ for an asset with returns modeled by an ARMA(1,1)-GARCH(1,1) model ...
3
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88 views

Extreme Value Theory for Value-at-Risk: Advantage versus historical simulation?

I started researching this topic and it is well covered in the literature. My understanding is that it uses a historical time series of returns of a given set of stocks and represent such ...
3
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223 views

Parametric VaR of a portfolio of a stock and an option on that stock

I understand how to calculate the parametric VaR of a stock and an option separately. But I don't understand how one can calculate the VaR of a portfolio of a stock and an option on that stock using ...
3
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931 views

'GARCH - extreme value theory - copula' approach to estimate risk measures in R

I'm reading about this approach of using GARCH-EVT-copula methodology to separate univariate and joint estimation and then estimate for example VaR and ES. I wanted to try something similar, but my ...
2
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0answers
59 views

Implied volatility surface modelling in filtered historical simulation

What is the best way to model implied volatility surface in filtered historical simulation (other than keeping it constant)? Is it appropriate to apply GARCH-like model to every point on the surface? ...
2
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305 views

RiskMetrics VAR calculations and conditional distribution of sum of log returns

According to Tsay's book in Chapter 7, for the Risk Metrics model: A nice property of such a special random-walk IGARCH model is that the conditional distribution of a multiperiod return is ...
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122 views

Modelling approaches for interest rate risk in the banking book (IRRBB)

I am having a hard time researching papers that deal with the measurement of market risk in the banking book. The trading book as I see it is similar to asset management and as the name says the ...
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62 views

VaR decomposition of non-normal portfolio by g-and-h distribution

According to Doowoo Nam (2013), VaR of non-normal portfolio returns approximated by g-and-h distribution can be decomposed pretty much in the same way as the VaR of a portfolio with normal returns. ...
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56 views

A priori selection of acceptable backtesting errors (type I and II)

Is it possible to a priori select an acceptable values of type I and II errors in backtesting (f.e. in case of the unconditional coverage test)? Type I error is directly connected to the significance ...
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0answers
1k views

How to fit a VAR + GARCH in R

I should create a VAR model with Garch error in R but i don't know how to do it and which package to use. The Vector Autoregressive model (or VECM) should also have covariates in it. Then I should ...
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323 views

Testing Statistical Significance of Various Portfolio Simulations

I'm trying to determine which of my portfolio simulations/backtests if any are good enough to put some money into. I outline an approach below and I'm interested in knowing: What problems are there ...
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0answers
865 views

Fixed Income Var calculation

I'm trying to calculate var for a portfolio of fixed income securities. I initially want to just calculate undiversified VaR for each instrument. I'm doing the following for each instrument Take ...
2
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1answer
156 views

Energy Risk Quant--Any discussion boards for energy related quant topics?

Any discussion boards for energy related quant topics? Like VaR in energy portfolio, and pipeline option pricing.. just want to know where is the best discussion board for such energy specific topics. ...
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75 views

Interpretation of Value at Risk

Let $X$ be a Loss random variable (Positive values of X represents Losses) and let $p \in (0,1)$. I know that the Value at Risk at level $p$ of $X$ is defined as: $$VaR_p(X) = inf{\{x \in \mathbb{R} : ...
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111 views

Value at risk, risk-neutral vs real-world probability measures

Does anyone know if there is any link between the Value at Risk of risk-neutral distribution and of the real-world distributions of asset rate of returns?
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52 views

Longer / Shorter period loss

I am struggling on I think a quite simple issue. Let's take a portfolio of 100 loans. If we assume they are independent, each loan’s default is a Bernoulli with parameter $p=0.01$ over a certain time ...
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0answers
45 views

Difference between Vasicek and Gordy models

I'm trying to understand what Gordy [1] added to Vasicek [2] model (the core of the IRB formula of Basel Accords). Is it correct to say the Vasicek shows that the portfolio loss conditional on $Y$ ...
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1answer
97 views

Can you predict MTM gain or losses on future contract?

I am working on a structured product where I am investing some percentage of invested amount in futures contract. I have created a bull put strategy and I will calculate the delta positions of that ...
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46 views

Advantage of copula over estimation based on historical data

It seems to me hard to intuitively understand the concept of copulas and their advantages. For example, why would it be better to estimate value at risk of portfolio by modelling its asset returns ...
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36 views

ES using historic simulation

Why is the data obtained from 91-100 days all eliminated from the calculation of the 1-day 95% ES? My interpretation is because the first day to calculate the 95% ES should be the 90th day? But I can'...
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365 views

Kupiec Test Backtesting VaR

I am currently analyzing the Kupiec test used for backtesting $VaR$. Suppose that I backtest a $VaR$ system for $n$ days (for example 250), with a confidence interval of $1-\alpha$ (for example a $1-\...
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1answer
339 views

Manually calculating and backtesting VaR and CVaR from DCC-GARCH R

I estimated a GARCH fit to the log returns of three series (CAC 40, a french real estate index and french T10 bond yield series) using rugarch. I then manually ...
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52 views

Does it make sense to subtract VaR from spot shocks?

I have a model to compute the Event Risk (in dollars) from a shock to the spot price of an asset. I also have the 10-day VaR PnL for the same assets returns. These two numbers are then aggregated to ...
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1k views

What should the half-life be in EWMA when calculating VaR from EWMA?

If we want to calculate an $x$-day VaR ($x$ is some time period in days) from an Exponentially Weighted Moving Average (EWMA) of vector of returns, what should the half-life in the decay factor in ...
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158 views

Monte Carlo VAR with differente asset classes

I have found a very useful post regarding the use of Monte Carlo simulaton to obtain portfolio Value at risk, based on Cholesky decomposition, random variates, etc. This post I'm talking about is: Is ...
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60 views

VaR calculation using excel gives different value than VaR using R at all c values except at c=0.5

This is VaR calculation in excel using variance-covariance method. This is VaR calculation in R. ...
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0answers
137 views

Value at Risk of a Portfolio

I am currently practicing for my Risk Management exam in July but my lecturer is of no help and my colleagues and I have no idea on how to proceed with this question. The past exam papers have similar ...
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51 views

VaR of future foreign currency income stream

Assume I have a series of future incomes in a single foreign currency. How do I calculate the total VaR for this forex risk using the volatility method? My first thought was that I could simply add ...
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0answers
87 views

Inference on bootstrap confidence intervals for VaR

I have calculated the confidence intervals of the VaR for two assets using iid bootstrap. I compute VaR using historical simulation (non-parametric). So I have two bootstrap confidence intervals (in ...
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0answers
104 views

How to understand quadratic finance or practice of Value-at -Risk(VaR)

We define the following notions for a jointly normally distributed random vector $P=(P_1,...,P_n)$ with f the density function. $$\mu=\int_{-\infty}^{\infty}(x_i-\mu_i)f_i(x_i)dx_i$$ $$\sigma^2_{ij}=...
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36 views

Making apriori Statements on VaR Backtests with a Garch Modelled VaR

so I want to find out, if its possible to find out for any backtest for the Value at Risk(Kupics POF or Christophersen's Markov Test), if it is possible to make apriori Statements on Testing results ( ...
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21 views

VAR Monte Carlo GBM vs Selecting Normal Dist Returns

I am running a VaR calculation and have seen two ways of doing it in several places online. One simply assumes normal distribution of returns and selects n number of returns from the normal ...
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0answers
30 views

Credit VaR for this portfolio assuming no default correlation and no recovery?

I am trying to estimate the Credit VaR for a portfolio of two risky bonds. The Credit VaR is defined as the maximum unexpected loss at a confidence level of 99.9% over a one-month horizon. Assuming ...
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0answers
17 views

VaR Back testing using Christoffersen and negative likelihood ratio (Excel file attached)

In order to backtest a VaR using the independence test of Christoffersen (1998) I calculate the following likelihood ratio (LR): My problem is that I land on a negative LR and: I don't know why this ...
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0answers
29 views

Backtesting VaR estimates

I'm going to perform a backtest on some VaR estimates (a huge sample) for a personal project. I'm wondering if the tests which are commonly used to evaluate VaR (Christoffersen, Kupiec) are in some ...
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0answers
20 views

Testing VaR accuracy on a large series of data

I'm going to perform a backtest on two VaR models on a very large dataset (+50.000 values). Normally, I would use the Christoffersen LR test but in my case, due to the very large number of observation,...
0
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1answer
64 views

question about significance level

A case study in a exam material goes like this: "Assume that the bank reports a daily VAR of \$100 million at the 99% level of confidence. Under the null hypothesis that the VAR model is ...
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31 views

Vasicek credit loss for real portfolio

Consider the Vasicek limiting distribution for losses of a loans portfolio. Now, consider a real portfolio, made of 10 loans each with a different rating class; eg: LN#1 - rating A+ LN#2 - rating BB ...
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34 views

VaR of protfolio with put and call

I've stumbbled into this question in a job interview and didn't know how to answer it: Calculate the VaR of a portfolio where you are long put and long a call
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19 views

Interpretation of Impulse Responses of VAR

Sorry for the dumb question. My model includes oil prices in level. So, for example CPI is log differences. I calculated IRFs of one standard deviation shock of real oil prices. How should I interpret ...
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0answers
48 views

A forward contract to buy a foreign currency can be handled by a linear model

In Hull's book, he says that: "An example of a derivative that can be handled by the linear model is a forward contract to buy a foreign currency." Then he continues with, "For the ...
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20 views

How to prove the following relation of Conditional Value-at-Risk and Value-at-Risk and Conditional Tail Expectation?

How to prove the following relation of Conditional Value-at-Risk and Value-at-Risk and Conditional Tail Expectation????
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35 views

Simulated VaR with differently distributed processes

I am attempting to calculate the one-month 95th and 99th percentile profits for a two-year portfolio of energy-generating assets over the next three months. This means that the calculation has two ...
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0answers
40 views

How to calculate VaR price space according to PRIIP flow diagram

My question is regarding the European regulation on standardizing the information in the KID's for PRIIPs. (https://esas-joint-committee.europa.eu/Publications/Technical%20Standards/JC%202017%2049%20(...
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67 views

Why is VaR metric still used?

It is well know that VaR is not subaddtive measure which means that condition $$ \text{VaR}(X+Y) \leq \text{VaR}(X) + \text{VaR}(Y), $$ where $X$ and $Y$ are portfolios, is not satisfied. As a ...