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.