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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80 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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Calculate Value at Risk for floating rate note

Consider a floating rate note: nominal: € 100 000 000 coupon period: annualy remaining time to maturity: 7 years and 3 months The coupon amounts to 3.3%, the current 3M-money market rate amounts to 3....
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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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28 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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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,...
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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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369 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 ...
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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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1answer
70 views

Calculate the VaR and ES for a confidence level of 99.5% [closed]

Question: The change in the value of a portfolio in three months is normally distributed with a mean of $500,000$ and a standard deviation of $3$ million. Calculate the VaR and ES for a confidence ...
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91 views

Total portfolio VaR greater than aggregated individual VaRs

I am facing something weird in a simulation. I have calculated a portfolio VaR: 100\$. Then I aggregated the VaR for individual position (loans) and obtain: 98\$. I thought it was not possible for the ...
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29 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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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
62 views

When is the VAR equal to the CVAR

After running an optimisation using a quadratic utility (CRRA) function I calculate an CVAR that is equal to the VAR especially for very small risk-aversion levels ($\gamma$=1 and $\gamma$=2 e.g.). ...
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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 ...
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1answer
33 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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1answer
80 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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33 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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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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1answer
49 views

Normal VaR for short bond

So I'm short a GBP denominated zero-coupon bond which has a face value of 1 million pounds and a remaining maturity of 6 months. Furthermore, I have to assume that the daily return of a 6-month zero ...
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47 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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19 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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34 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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1answer
41 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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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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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? ...
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1answer
78 views

Resources on VaR modelling for derivative portfolios?

I'm interested in finding resources related to historical VaR calculation for derivative portfolios where both spot and implied volatility changes are accounted for. The resources I've been able to ...
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1answer
54 views

Incremental/marginal contribution to VaR in a simulation setting

Estimating marginal contributions to VaR in a simulation setting is apparently quite difficult (see e.g. this blog post) due to issues with sampling variability. My question is whether the following ...
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45 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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1answer
88 views

Value at Risk (VaR): Normal distribution with gamma distributed volatility

If I was to do a 99% VaR calculation on a portfolio with normally distributed returns $\mathcal{N} (\mu,\sigma)$, the 99% VaR would be $\mu - 2.33\sigma$. Instead of having a constant volatility, let'...
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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 ...
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1answer
111 views

How do you handle implied volatility performing a VaR Monte-Carlo simulation using a stochastic volatility process calibrated on the underlying

Say you have a portfolio consisting of options each having a market implied volatility. If you now use some stochastic volatility model like GARCH to calibrate the real world volatility of the ...
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1answer
82 views

Portfolio VaR of a hedge portfolio (long index, short future): What total exposure to take to calculate VaR?

Imagine a portfolio is made of 20m USD invested in equities and -18m USD of MSCI World futures (sell 18m USD short). The annualised volatility of the 20m USD in equities (Equ.) is 15% and the ...
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1answer
37 views

Summing up two VaRs

I know that normally you can't just add two VaRs straight ahead and you need to use the formula with the sum of squares and the square root. However, in the marking scheme for the task in the image ...
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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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313 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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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 ...
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Payment Gateways' market risk: where does it come from?

Companies like Square and Adyen and Paypal are flourishing. They facilitate payments between people and business in various currencies and provide small loans. However as they are not banks they are ...
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230 views

Credit VaR Formula

in Chapter 23 of Hull's Options, Futures, and Derivatives he has an example (i.e. example 23.4) which shows how the Credit VaR formula is applied. The answer in the formula is 0.128. I can't seem to ...
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1answer
217 views

Analytical portfolio optimization for VaR under multivariate normality

Given a set of assets with returns following a multivariate normal distribution with a known mean vector and a known covariance matrix, $$ r \sim N(\mu,\Sigma), $$ I want to find optimal portfolio ...
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1answer
301 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
370 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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1answer
54 views

Problem in calculating a simple VaR

In Alexander, Gordon J. and Alexandre M. Baptista (2006). Does the Basle Capital Accord reduce bank fragility? An assessment of the value-at-risk approach. Journal of Monetary Economics 53(7), ...
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247 views

Missing data in historical simulation VaR

A historical simulation approach to VaR estimation relies on the availability of historical data. What do we do when there is no data (say, spot price and implied volatility surface) as, for example, ...
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66 views

How to calculate value at risk in accordance with Basel?

I would greatly appreciate if you could let me know whether Value at Risk should be calculated for net open position (foreign currency assets-foreign currency liabilities) or for foreign currency cash?...
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2answers
143 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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Approximation of portfolio VaR (after mapping) when Delta and Gamma both equal zero

As titled, I am having trouble estimating the VaR of a portfolio mapped as a function of a single risk factor $S$, in the form : $$V(S) = S^3 - 30S^2 + 300S + 150$$ with current value $S = 10$. $S$...
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How to add Risks-Not-In-VaR (RNIV) to VaR under Basel III

I am trying to generate/prove the magnitude of the over-conservativeness of the regulatory VaR (internal models) under Basel III against what a more accurate VaR would be. However, I can't seem to ...
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1answer
79 views

A quick and dirty loss distribution and Credit VaR

I need to create a loss distribution for a credit portfolio as the first steps to estimate the portfolio Credit VaR. I have historical monthly account snapshots (payment history) of all accounts ...
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1k views

1 day VaR vs 10 day VaR

Even while using historical simulation VaR, 1 day VaR is converted into 10 day VaR by multiplying 1 day VaR by Sqrt(10) for regulatory reporting purposes. What are the underlying assumptions for ...
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1answer
268 views

VaR equivalent volatility meaning

I have a hard time with interpreting VeV. I mean - I see its just standard deviation derived from Cornish-Fischer VaR, but I don't really know how to interpret it. The formula for VeV is: ...

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