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1answer
142 views

Currency risk USD>EUR>EGP

Seeking input on hedging risk on USD to Euro with a 3rd component of payroll issued in Egyptian Pounds. We are a US corp invoicing a Germany entity in Euro with massive payroll being paid in Egyptian ...
1
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1answer
121 views

CDS spread scenarios from historical market data

I'm searching for information on the best way to generate scenarios to be used in VaR or ES calculations, for CDS spreads. Given that we need significant historical data in order to achieve a decent ...
3
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1answer
315 views

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 ...
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2answers
75 views

Parametric VaR of a portfolio including a swap

I am calcualting the parametric VaR of a portfolio that includes among other things an IRS swap that begins in the exact same day the valuation is done. Therefore, its NPV is 0 and I do not which ...
3
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1answer
46 views

Can I split my backtesting into multiple consecutive sub-periods?

I'm testing a model to estimate the VaR of a portfolio with different stocks. I used 1500 data to estimate some parameters, and now I have other 1500 data for backtesting purposes (for a total of 3000 ...
3
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1answer
54 views

Overestimating or underesitmating risk?

This question might be silly, but I want to be sure of myself. If one has Value-at-Risk forecasts and there are zero VaR breaches (i.e. no return value is smaller than or equal to the VaR value) then ...
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0answers
21 views

help with p&L vectors historical simulation

My question is about the calculation of the Value at Risk based on historical simulation. I have a table which contains the P&L-vectors of each day of one year. But I don't know what is contained ...
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0answers
27 views

Estimating VaR (Value At Risk) with only 3 days of data

I've been given daily stock prices on Day 1, 2 and 3 for 10 stocks (hence 30 data numbers in total) and asked to approximately the 1-day 95% VaR (Value at Risk) on Day 3. I'm not allowed to use any ...
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3answers
192 views

Step By Step method to calculating VaR using MonteCarlo Simulations

In trying to find VaR for 5 financial assets with prices over a long period of time(2000 days worth of data) how would I do the following: Carry out monte-carlo simulation in order to find a VaR ...
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0answers
42 views

Problems in computing VaR with GARCH-GPD-copula approach

I use a time-varying Gaussian copula (with GARCH-filtered standardized residuals modeled semiparametrically with Gaussian kernel interior and GPD tails, i.e. generalized pareto distributed) to ...
3
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2answers
59 views

Do you know fast to compute, yet plausible risk attribution measures?

I am looking for a fast to compute, yet plausible risk attribution measure based on the risk measure used to compute overall risk. To be more specific, assume that my risk measure is the VaR of a ...
2
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2answers
43 views

Maximization with risk-neutral investors and VaR constraints

In this paper, the authors make a simple model with: (1) A global bank, who is risk-neutral but has a Value-at-Risk constraint: $$\max_{x_t^B} E_t[x_t^B\prime R_{t+1}]$$ s.t. $$\alpha (Var(x_t^B\...
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1answer
41 views

Calculating VaR of an Incomplete Distribution

I am currently completing a multiple choice question that has stumped me. An asset has its price and its corresponding probability described as: 100, 0, -50, -70 and -90 with probabilities 50%, 12%...
1
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1answer
64 views

Issues in estimating VaR with GARCH

I am currently trying to figure out how to estimate the value at risk using the rugarch package in R. I've come to a result, but it seems a bit excessive. Here's my code: ...
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0answers
44 views

Coherent Risk Measures and VaR

I am working on a problem that is worded exactly as follows: Consider the functions $\rho_{1}$ and $\rho_{2}$, defined on the space of random variables with finite expected value in the following way ...
4
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1answer
89 views

Backesting VaR on overlapping intervals to year's end

Let us assume that each month of the year (up to November) we calculate a VaR (say 99%) with holding period to the end of the year. Thus the holding period starts with 12 months and goes down to 1 ...
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0answers
161 views

How to backtest Value at Risk Models using Conditional and Unconditional tests?

I am trying to carry out backtesting on a number of Value at Risk figures i obtained using var/covar, historical, and monte carlo simulation. The two methods im using are the Kupiec test (...
1
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1answer
119 views

Is Value-at-Risk translation invariant?

Let: $X=V_1-V_0R_0$ where $R_0$ is the interest rate. Then, is it so that this risk measure is Translation Invariant as: $\textit{VaR}_{\alpha}(X)=\textit{VaR}_{\alpha}(V_1-V_0R_0)=V_0+\textit{VaR}_{\...
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0answers
77 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 ...
1
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1answer
139 views

Calculate VaR for a liabilty taking a exponential distribution?

An insurance company faces the liability loss off $L = \begin{cases} 0, & \mbox{with probability } 0.75 \\ Z, & \mbox{with probability } 0.25\end{cases}$ where $Z\sim Exp(\mu)$. I want to ...
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2answers
59 views

Value-at-Risk “hiding risk in the tail” and diversification?

I have a question regarding Value-at-Risk and diversification? When one says that VaR "hides the risk in the tail", does one mean that if we for instance look at VaR at level p=0.05 say, we might get ...
1
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1answer
47 views

Value at risk in dollars vs. log returns

I have a quick question about this remark in Tsay's book "Analysis of Financial Time Series" (3rd edition). He says that $$ \text{dollar VaR} = \text{Value} \times \text{log return VaR} $$ and that ...
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0answers
100 views

Simulating Option Positions VaR with Monte Carlo in Python

I'm trying to calculate VaR for overall option positions. Currently I do a MC simulation for the underlying, and derive the theoretical value of the option from those theoretically. Then I calculate ...
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1answer
42 views

Value at Risk Theory [closed]

I am having a bit of trouble disseminating the true meaning behind VaR. Say you have two V Values, prior to taking ABS value. Both values are negative, the first value being -10 and the second value ...
2
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3answers
3k 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. ...
1
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1answer
70 views

Where can I find Value at Risk & Expected shortfall for ETF's?

I'm struggling to find VaR & ES data for ETF's on websites such yahoo finance & Morningstar. Where can I find this data? Thanks,
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1answer
501 views

Value-at-Risk formula when using skewed-t distribution

I am trying to find a formula for the skewed-t VaR. For example the VaR formula for a t-distribution is $$ \sqrt{\frac{df-2}{df}} \times \Sigma{t} \times \mbox{quantitle}(t-\mbox{dist}, 0.01) + \mu $$...
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0answers
44 views

Intraday Value at Risk approximations

We use full valuation of derivatives portfolios using scenarios from historical data. For simple contracts, this is relatively fast. For contracts requiring monte carlo simulation, this becomes ...
0
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1answer
51 views

VaR interpretation for positive returns

I used Extreme Value Theory to separate extreme negative returns from extreme positive returns, then, I calculated the VaR for both. I need to know what could be the interpretation of VaR for ...
2
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2answers
2k views

Does one use the covariance or correlation matrix in cholesky decomposition to generate correlated samples

Can we interchangeably use Cholesky decomposition of covariance and correlation matrix to generate simulations? If not, in which situations do we use one or the other and why? Thanks in advance.
2
votes
1answer
613 views

Parametric VaR with Student-t distribution

Im using VaR to estimate parametric VaR. I have been able to do this using a Normal Distribution, however I want to also do this using a Student t-distribution and I'm unsure how to implement that in ...
2
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1answer
71 views

How to measure the volatility of illiquid bond with no historical prices

The basket of corporate bonds that I am following barely traded after the issuance. Hence, there is no historical data to estimate the volatility. Can you suggest me a different approach to come up ...
2
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1answer
49 views

Expected Shortfall alternative formulation

Define: $$q_\alpha(F_L)=F^{\leftarrow}(\alpha)=\inf\lbrace{x\in \mathbb{R}\mid F_L(x)\geq \alpha\rbrace}=VaR_\alpha(L)$$ I want to prove that: $$ES_\alpha = \frac{1}{1-\alpha}\mathbb{E}[\mathbb{1}_{...
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0answers
49 views

Value-at-Risk Calculation with respect to the Capital Requirements

I want to calculate the Value-at-Risk at date $t$ in such a way that I minimize the capital requirements given as \begin{align} \text{CR}_{\,t+1\,:\,t+250} = \sum_{h=0}^{249}\max\left( -(3+k_{t})\...
2
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0answers
115 views

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 ...
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1answer
71 views

Value-at-Risk of the sum of three independent lognormal random variables with different confidence level

there are three Business units in a firm, each has operational VaR value which are independent from eachother. the quantile for each opVaR is different from the others. can I simply add the VaRs to ...
1
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1answer
129 views

What is the difference between these two Expected Shortfall definitions?

I have come across different ways expected shortfall is defined. e.g. $$ES_a(X)=\frac{1}{1-a}\int_a^1VaR_b(X)db$$ and $$ES_a(X)=\frac{1}{a}\int_0^aVaR_b(X)db$$ e.g. on Wikipedia's article. Are these ...
1
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1answer
233 views

Quantiles, Value-at-Risk and log normal random walks…

Sorry, that's probably quite a bunch of silly questions, but I just got lost a bit and need to dot all the i's and cross some t's :). Let's say we have a series of returns (like this one we may get ...
4
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1answer
301 views

Overlapping Value-at-Risk Backtest Data an Issue?

My understanding of VaR model back testing is thus: ~~ t: Calculate daily VaR using look back data over n past days t+1: Compare daily return against VaR, record breach if one occurred, repeat ...
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4answers
140 views

How to extrapolate VaR?

I have a model predicting 1-day VaR. How does 1-year VaR follow from it? Shall I just multiply by 365 or another method?
4
votes
1answer
191 views

Portfolio VaR with Copula?

Let the portfolio be given by: $$X=X_1+X_2$$ $(X_1,X_2)$ are dependent through a Copula function $C(u_1,u_2)$, such that the joint distribution is given by: $$F(x_1,x_2)=C(F(x_1),F(x_2))$$ What is ...
3
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2answers
71 views

CVaR reformulation correct?

Conditional Value at Risk (CVaR) is given as: $$CVaR_\alpha(X)=\frac{1}{\alpha}\int_{0}^{\alpha}VaR_\beta(X)d\beta=-E(X|X\leq-VaR_\alpha(X))=-\frac{1}{\alpha}\int_{-\infty}^{-VaR_\alpha(X)}x \cdot f(x)...
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0answers
112 views

Beta distribution - Holding period

Let's say I have a risk factor that is defined between [0,1], such as recovery rates. Assuming I have daily data, I can estimate the "daily VaR", i.e. the tails over 1 day period, since the data is ...
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1answer
179 views

questions on VAR manipulation

The book of Financial Risk forecasting by Danielsson gives the following example about VAR manipulation. I have two questions: 1) If $0> VAR_1 > VAR_0$ , why the following figure plots it as $-...
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2answers
315 views

Historic Value at Risk - Ratios vs. Differences

Quick Summary on Historic VaR Let $S_0,...,S_n$ be the daily values of some stock (where $S_0$ is the current value). Then for $i=1,\ldots,n$ we let $$\hat r_i:=S_{i-1}/S_i \quad \text{and}\quad \hat ...
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4answers
711 views

How can I calculate Value at Risk?

Is it possible calculate Value at Risk on an asset without a time horizon? What kind of variables do you need? Variables that are on the table are value, standard deviation, beta, market return, risk ...
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1answer
159 views

regarding Basel II III model

I may have to get involved in some projects using Basel II, III model for risk modeling, to which I have no background. Are there any good book/tutorials to recommend? What are the underlying ...
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2answers
384 views

CVaR/VaR Ratio as alpha goes to 1

I am having trouble taking the following limit of CVaR/VaR for a normal distribution as alpha approaches 1: $\lim_{\alpha \to 1} \frac{\mu + \sigma \frac{\phi^{-1}(\alpha)}{1-\alpha}}{\mu + \sigma \...
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2answers
596 views

Estimation of Empirical Expected Shortfall of a heavy tailed distribution

Assume that you have a portfolio for which you have estimated a parametric model to the underlying instruments, but the distribution of the portfolio as a whole is too complicated to compute ...
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0answers
272 views

Comparing Backtests of Value-at-Risk and Expected Shortfall

My goal is to test if ES (CVaR) empirically is a better risk measure than VaR for a set of given variables (assumed underlying distribution, confidence level, sample size) for different asset classes. ...