Many popular techniques for determining a securities firm's value-at-risk are based upon the calculation of the historical volatility of returns to the assets that comprise the portfolio and of the correlations between them. One such approach is the JP Morgan RiskMetrics methodology using...

There is much evidence in the literature that the volatility of asset returns, in particular those from stock markets, show evidence of an asymmetric response to good and bad news. This paper considers the impact of news on time varying hedges for financial futures. The models are compared with...