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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143 views

How to adjust corporate actions for VaR

I am using variance co variance matrix for calculating the VaR. Now if the some corporate action comes in between like stock split, resulting a huge VaR number on that particular day as the volatility ...
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168 views

Monte Carlo VaR assuming logistic distribution

I have a Monte Carlo model which measures the Value at Risk (VaR) for given portfolio. I use the geometric brownian motion to model the prices. But let's say I assumed the returns of prices follow the ...
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1answer
145 views

Why normalize only data for CDSs for PCA?

I'm reading a Credit Suisse Research Report on PCA. The report says that to preprocess the data, you should "Centre data (and normalize when considering CDS data)." Why would you only normalize ...
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95 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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132 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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54 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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87 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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49 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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37 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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637 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
477 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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1answer
519 views

Calculate the historical simulation VaR of the portfolio using Python

Assume that we have 200 stocks in WeiBo (WB), 300 stocks in Netflix (NFLX), 250 stocks in Ford Motor Company (F) and 150 in Royal Dutch Shell (RDS-A) as of 31 August 2019 in the portfolio. I have ...
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213 views

Compute the VaR from NPV (Net present value)? [closed]

A client is evaluating an investment in Indochina requiring an initial expenditure (period 0) of 10,000, and which then in periods 1 and 2 gives a benefit V1 and V2. Assume that the discount rate to ...
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53 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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73 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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1answer
103 views

Value at Risk for normal r.v. with shock (regimes)

I am struggling to understand how was this simple Value-at-Risk calculated. It's Example 1 in Daníelsson, Jón, et al. "Fat tails, VaR and subadditivity." Journal of econometrics 172.2 (2013): 283-291 (...
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153 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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89 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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57 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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108 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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2answers
763 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 ...
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37 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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169 views

Understanding the VaR example on wikipedia

In the wikipedia page on VaR The example says: ...
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3answers
89 views

What information should be delivered to the client so they have enough information to manage their exchange rate risks? [closed]

The client can be a CFO or CEO. The information can indicators, charts, graphs, statistics, ratios, etc. I know the VaR is one of them.
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1k views

It is possible to carry out the Component VaR decomposition through non parametric methodologies?

I would like to know if it is possible to break down the VaR risk (using historical and Monte Carlo methodology) among the portfolio assets just like the Component VaR concept in the parametric ...
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46 views

Testing severity of VaR by changing portfolio component weights

Let's assume that I have a portfolio with two components:$$\omega_i = 0.3$$ $$\omega_j = 0.7$$ I also have two P&L vectors, $v_i$ and $v_j$ each containing 1000 P&Ls. I would like to play ...
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2answers
130 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 ...
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1answer
51 views

Is scaling the standard deviations in the VaR formula (parametric) equivalent to scaling the VaR figure at the end?

I have come across people calculating parametric VaR who scaled the standard deviations by say square root of 10 to scale up to a 10 day horizon. Elsewhere I have seen textbooks suggesting that it is ...
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1answer
275 views

VaR for Options portfolio

I'm asked to estimate VaR for Options portfolio. Firstly, I wanna try to estimate VaR for AAPL stock european call option using Historical Simulation but I can't find any Historical Data. I tried ...
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2answers
195 views

Calculation VaR on long term period

I'm calculating VaR numbers from historical data for a single instrument (it's plain vanilla, not a derivative) and receive such variables: I could provide necessary data, and formulas but I guess ...
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1answer
3k views

Difference between Delta-Gamma and Delta-normal method for VaR

I was reading the differences between Delta-Gamma and Delta-normal method for VaR. One of the difference I found is mentioned below, but I can't understand it's importance. Can anybody please explain ...
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1answer
73 views

Solving for volatility of a portfolio via its components

I have only been able to find the calculation for computing volatility for two assets, and I don't believe one can solve for covariance of $n$ assets where $n>2$ . Is there a method for solving for ...
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2answers
430 views

Value At Risk for Long and short position with same maturity and same traded price

I am not a quant geek.I always have doubt what should be the VaR output for portfolio contains long and short of the same maturity @ same traded price. e.g. CME corn future of sept expiry ...
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1k views

Is it OK to consider the expected return is zero for stocks when calculating VaR over a short horizon?

I want to implement the approach described in the following recipe for calculating VaR: Is there a step-by-step guide for calculating portfolio VaR using monte carlo simulations I was told that I can ...
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2answers
1k views

How to compute the historical VaR for a portfolio with long and short positions?

I would like to calculate historical Value at Risk for a portfolio that includes both long and short positions in forward contracts. The part that confuses me is that I wonder whether the VaR of the ...
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1answer
65 views

VAR of Long & Short European Call Options

I have over 1000 simulated stock prices for an option that is expiring in 3 months. I have calculated the EU call option payoff of 1000 simulated prices and now I have 1000 simulated payoffs of call. ...
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1answer
73 views

Standard market risk platform Value-at-Risk (VaR)

if possible, could you share publicly available methodological guides/pamphlets or post links to specialised websites which give sufficient detail of the basic assumptions, algorithms and possible ...
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2answers
87 views

10-day VaR for a portfolio

So, Bank ANZ owns a portfolio of options on the USD/GBP exchange rate. The delta equivalent position of the portfolio is GBP 56.00. The current exchange rate is 1.5, with a daily volatility of 0.7 ...
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46 views

Lead-lag bivariate VAR model

I am really interested in Granger-causality. Can anyone think of a paper that uses a bivariate VAR model in economics or finance?
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52 views

the relationship between VaR(0.05) and mean?

What is the meaning of the difference between the quantile of prob=0.05 and mean for a sample form a specific distribution? In other words, I would like to understand the relationship between ...
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2answers
156 views

understanding Value-at-Risk correclty

The are several types how to calculate the VaR. I am focussing on the method of calculation the VaR in percentage. $VaR=I*z*std*\sqrt{t}$ This gives the VaR in €. I have the z-value, the daily ...
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175 views

Value at Risk Calculation

In historical simulation VaR, if we have stale data for some of our risk factors, which means daily returns on a particular risk factor is 0 on multiple occasions. Is there any way to solve this other ...
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2answers
102 views

Parametric VaR assumption question

Why do you have to make a correlation matrix when calculating the parametric value at risk, if one of the assumptions for this method to work is that the assets of the portfolio must be independently ...
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1answer
217 views

How to regard foreign currency forward as foreign and domestic bonds on VaR

In John Hull's book Options, Futures and Other Derivatives 9th page 507 We want to calculate the VaR of a ...
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1answer
2k views

Backtesting Value at Risk. With kupiec test

I have a certain problem with backtesting calculated earlier Value at Risk. I've got calculated daily VaR with historical simulation method for stocks. I've used two values of alpha 0.05 and 0.1. Now,...
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1answer
179 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 ...
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2answers
102 views

How to predict VaR changes on a DoD basis?

I am trying to predict change in VaR on a DoD basis. So let's say at t=0, I have my VaR based on full valuation. On t=1, I will have another VaR based on full valuation. I am trying to predict this ...
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1answer
1k views

Variance covariance matrix for a portfolio containing bonds also with other asset classes

What should we take for a bond or a zero coupon bond in order to make a variance covariance matrix? For example:- Equities - we take the market price Cash - we take the spot rates Bonds - Do we take ...