Poroflio part 5 Flashcards
(77 cards)
What does Value at Risk (VaR) measure?
VaR measures downside risk: the loss size, probability of exceeding that loss, and a time frame.
What are the three components of VaR?
Loss size, probability, and time frame.
How is VaR typically expressed?
As a dollar loss, percentage loss, or confidence level (e.g., 95% confidence for 5% VaR).
What probabilities are common for VaR reporting?
1%, 5%, or 16% (one standard deviation below the mean for normal distribution).
What is the parametric (variance-covariance) method for VaR?
Assumes normal distribution; uses means, variances, and covariances to estimate VaR.
What is the formula for portfolio variance (two assets)?
σ²_portfolio = WA²σA² + WB²σB² + 2WAWB Cov_AB.
What is the lookback period in VaR estimation?
The historical time period used to estimate mean and variance for returns.
What are the weaknesses of the parametric method?
Relies heavily on normality assumption; not suitable for portfolios with options.
What is the historical simulation method for VaR?
Uses actual historical changes in portfolio value without assuming any distribution.
Strengths of historical simulation method?
No assumption of normality; captures non-linear risks like options.
Weaknesses of historical simulation method?
Depends heavily on the sample lookback period; may overestimate or underestimate VaR.
What is the Monte Carlo simulation method for VaR?
Simulates random values from assumed distributions for risk factors; calculates portfolio changes thousands of times.
Strengths of Monte Carlo simulation?
Flexible with distribution assumptions; handles complex portfolios and non-linearities.
Weaknesses of Monte Carlo simulation?
Dependent on assumptions about distributions and correlations; computationally intensive.
When would Monte Carlo and parametric methods produce identical results?
When the distribution and parameter assumptions are the same and sample size is large.
Example: In a portfolio of $10M, if 5% daily VaR = 2.06%, what is the loss amount?
206000
Example: In the same portfolio, if 5% annual VaR = 24.09%, what is the loss amount?
2409000
What are advantages of VaR?
Simple concept, compares risk across portfolios, used for performance evaluation, risk budgeting, accepted by regulators, and backtestable.
What are limitations of VaR?
Affected by assumptions, normality assumption underestimates tail risk, ignores liquidity risk, correlation spikes during stress, incomplete risk capture.
What is Conditional VaR (CVaR)?
The expected loss given that the loss is equal to or greater than the VaR (expected shortfall).
What is Incremental VaR (IVaR)?
Change in portfolio VaR resulting from a change in the portfolio allocation to a security.
What is Marginal VaR (MVaR)?
The slope of the VaR curve at the current weight; approximate change in VaR for a 1% increase in a security’s weight.
What is relative VaR (ex-ante tracking error)?
VaR of the difference between the portfolio return and benchmark return.
What does sensitivity analysis measure?
Effect on portfolio value of a small change in a single risk factor; complements VaR.