Showing posts with label market risk. Show all posts
Showing posts with label market risk. Show all posts

Sunday, August 7, 2011

Market Risk Assessment -2

Using a single number, indicate the VaR of a portfolio exposure to market risk and the likelihood of loss under the conditions proposed. The risk is also measured in monetary units, the same as those in which balances are established. Finally, among its other benefits, VaR:

* To evaluate the performance and correct any risk-based.
* Promote the information and transparency to the extent that it is a measure expressed in non-technical terms and may be subject to periodic reports.
* To determine the allocation of funds to invest and set quantitative limits for risk managers.

Three calculation methods are generally used to estimate the distribution of losses. They have in common to estimate the potential change in portfolio value from the data of the past, however, differ on the following:

* The historical method: observation of the historical behavior of the position to estimate the VaR;
* The parametric method: decomposition of the position of instruments based on different risk factors (equity indices, rates of different maturities, exchange rates ...) and then estimate the probability distribution of risk factors;
* The Monte Carlo simulation Monte Carlo market factors from an a priori probability distribution and estimate the VaR, as the historical method, from the sample generated.

Market Risk Assessment -1

Quantification of risk is a major concern of financial players because it allows them to answer questions like "How can we lose with our portfolio in normal market conditions or abnormal for a time horizon given? ". VaR (Value at Risk) and Stress Testing are the two most common methods of quantification of risk and are usually combined.

Although the VaR can be used as a baseline measurement for all types of risk and the overall level of society, its most common use for market risk.
VaR is a probabilistic measure of the loss of a portfolio point of a given composition as a result of future changes in risk factors. It is defined by the maximum probable loss at a confidence level of x% (for a time horizon of one day / one week, etc.).. Var corresponds to the loss that will not be exceeded in more than (100-x)% of cases, when a position given structure is maintained for a period [0, T].

If Vt is the value of the position t, the VaR is given by:
Pr {Vo - VT} ≤ ≥ VaR (100 - x) / 100

For example, consider a portfolio for which the VaR of € 100 million with a confidence level of 99% over a period of one week, meaning that, under normal market conditions, there is a probability of 1 % to record a loss of more than € 100 million for the week of detention (period over which the change in value of the portfolio is measured).