We construct a dynamic competitive model with futures markets where price volatility comes from information arrival and noise trading. In this model, we address three issues: What does informational efficiency mean in a multi-period setting? How do information arrival and noise trading interact...

We study the correlation of monthly excess returns for seven major countries over the period 1960-1990. We find that the international covariance and correlation matrices are unstable over time. A multivariate GARCH(1,1) modelling with constant conditional correlation helps capture some of the...