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Questions tagged [value-at-risk]

Value-at-Risk is a family of measures used to help the owner of a position to assess its "worst case value".

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Is there a step-by-step guide for calculating portfolio VaR using monte carlo simulations

I am trying to determine a step-by-step algorithm for calculating a portfolio's VaR using monte carlo simulations. It seems to me that the literature for this is extraordinarily opaque for something ...
BigONotation's user avatar
11 votes
3 answers
10k views

How does Cornish-Fisher VaR (aka modified VaR) scale with time?

I am thinking about the time-scaling of Cornish-Fisher VaR (see e.g. page 130 here for the formula). It involves the skewness and the excess-kurtosis of returns. The formula is clear and well ...
Richi Wa's user avatar
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10 votes
2 answers
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Empirical distribution function of overlapping time series data

If we model asset return volatility for periods of more than one (say more than one day) there is the square-root rule which holds true under some assumptions. The situation is more tricky if we look ...
Richi Wa's user avatar
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10 votes
2 answers
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How is the formula for the VEV (VaR-equivalent volatility) in the PRIIP document derived?

The recent regulation (page 32) on PRIIPs requires to compute a VaR-equivalent volatility defined as $$\mbox{VEV}=\frac{\sqrt{3.842-2\ln \mbox{VaR}}-1.96}{\sqrt{T}}$$ Does anyone have an idea how ...
splinter123's user avatar
23 votes
5 answers
16k views

Portfolio optimisation with VaR or CVaR constraints using linear programming

I would like to optimize a portfolio allocation (maximizing the exposure or the expected return), but with VaR or CVaR contraints. (some parts of my portfolio cannot exceed a certain VaR) How can I ...
RockScience's user avatar
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18 votes
1 answer
623 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 ...
dsm's user avatar
  • 283
12 votes
4 answers
3k views

Are these steps correct to calculate Value-at-Risk with a Monte Carlo simulation?

I have a problem calculating VaR with the Monte Carlo Simulation. I followed the next steps and would like know if it is a right way to calculate VaR or if I need something more? The steps Generate ...
maria's user avatar
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7 votes
1 answer
2k views

Question regarding the Category 3 PRIIP MRM calculation

My question is regarding the European Commission regulation on standardizing the information in the key information documents for PRIIPs. In the Annex IV of the regulation, one can find the ...
Boris's user avatar
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7 votes
2 answers
2k views

VaR mapping - Forward Foreign Currency Contract

I have a question about VaR mapping for FX forwards. Please bear with me while I outline the problem. Philippe Jorion's book discusses VaR mapping; a means to break down complex instruments into ...
AfterWorkGuinness's user avatar
7 votes
2 answers
4k views

Value at Risk for Futures Contracts

I would like to know how you would compute Value at Risk on a portfolio of futures i.e rates futures, commodity futures and equity. How do you deal with the discontinuous form of commodity futures for ...
Sitingbull's user avatar
5 votes
4 answers
2k views

How to determine what's driving the VaR?

I am given the following data: Historical (260 days) P&L vector of a portfolio. Specific P&L's for each investment in the portfolio, for the 10 days with the lowest P&L. The question ...
Mkch's user avatar
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5 votes
2 answers
11k views

non-subadditivity of VaR

I have been reading up on VaR and get very confused by the subadditivity concept. On wikipedia, it says "VaR is not subadditive: VaR of a combined portfolio can be larger than the sum of the VaRs ...
codeedoc's user avatar
  • 245
5 votes
0 answers
840 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, ...
Quartz's user avatar
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3 votes
1 answer
11k views

Historical Value At Risk on option portfolio

I am new to Value at Risk subject in fact everything related to quant. Can any body validate the Value at Risk Model on the option price ? I am using a below explained approach . our portfolio ...
user1131338's user avatar
2 votes
1 answer
146 views

Understanding VaR rescaling

Assume my portfolio has a current market value of $V_0$, that the daily returns are independent and identically distributed as a normal distribution $N(0, \sigma^2)$ and that there are $N$ trading ...
augustoperez's user avatar
2 votes
3 answers
18k views

Why is Value at Risk non-negative?

When reading the book of Financial Risk Forecasting, I saw the following example. I am not very clear about two points marked with yellow and green respectively. ...
user288609's user avatar
2 votes
1 answer
310 views

Questions about VaR and CVaR. Is there any relation between $VaR_{\alpha}(X)$ and $VaR_{\alpha}(-X)$, or $CVaR_{\alpha}(X)$ and $CVaR_{\alpha}(-X)$?

I have some questions when dealing with Value-at-Risk (VaR) and Conditional Value-at-Risk (CVaR). Is there any relationship between $VaR_{\alpha}(X)$ and $VaR_{\alpha}(- X)$, or $CVaR_{\alpha}(X)$ ...
Xinyuan's user avatar
  • 47
1 vote
2 answers
203 views

VaR backtesting. Reasons for over- and underestimation of value at risk estimates?

I use an ARMA-GARCH model for univariate distributions and a copula model for the multivariate distribution. For the value at risk (VaR) estimation, I do a Monte Carlo simulation. I'm looking for some ...
daxson's user avatar
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1 vote
1 answer
6k views

VaR for FX forwards

I am trying to figure out some of the commonly used approaches to deal with FX forwards (in a currency portfolio containing spots, forwards and swaps) that would allow me to calculate the one day VaR ...
ali haider's user avatar
1 vote
3 answers
1k views

Can a VaR equivalent Volatility (VEV) be negative?

As from title, can a VaR equivalent Volatility (VEV) as defined by KID/PRIIPS law be negative?
Thegamer23's user avatar
1 vote
1 answer
465 views

Prove Subadditivity - Entropic Value at Risk

Any insight in how to prove the following risk measure is subadditive? $\rho_{1-\alpha}(X) = \inf_{z>0}\{z^{-1}\ln(\frac{E[e^{zX}]}{\alpha})\}$, with $\alpha \in ]0,1]$ I want to prove it is a ...
Amy Zhang's user avatar
1 vote
0 answers
786 views

Large deviations theory and extreme value theory

I'll enter into details of both, sooner or later, but for the moment I'm concerned about the differences (and relationships, if any) between these two theories. Can someone give me a brief, but still ...
simmy's user avatar
  • 585
0 votes
1 answer
330 views

What does "1-month horizon" mean in VaR calculations

For a simple equity portfolio, I need to compute historical 1-year simulation VaR with a "1-month horizon". I imagine this means I need to compute the 1-month return of the portfolio at each point in ...
lebelinoz's user avatar
  • 274
0 votes
1 answer
3k views

Compute cross-gamma

I am trying to use delta-gamma method with montecarlo simulations to calculate the VAR of a portfolio consisting in options and equities. To use the method I need to compute a gamma matrix, that has ...
FernandoG's user avatar
0 votes
2 answers
409 views

recalculate VaR from one currency to another

I have a strange question. For example, I have 95% VaR (1Y, delta-normal) for portfolio with one stock in same currency (for example, USD). What minimal information should I have for recalculation ...
Dmitriy's user avatar
  • 243
0 votes
1 answer
4k views

How does delta-gamma VaR work in practice and when can it be preferable to Monte-Carlo VaR?

So I will start off by just stating my understanding of the two methods through some examples and lead that into my question. Hopefully it is correct but if not then perhaps the answer to my question ...
Oscar's user avatar
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0 votes
1 answer
737 views

VaR on Interest Rate Swaps

I am a newbie and was after a simple explanation on how VaR is calculated for a portfolio of IRS's.
Andy's user avatar
  • 101
0 votes
3 answers
1k views

Parametric/Analytical VaR

Suppose I want to calculate VaR for a known distribution with mean $\mu$, variance $\sigma^2$ and $\alpha$-quantile as, $VaR_{\alpha}$ = $\mu + \sigma q_{\alpha}$. For a Gaussian distribution it is ...
Kumar's user avatar
  • 613