We investigate whether stock betas vary with the release of firm-specific news. Using daily firm-level betas estimated from intraday prices, we find that betas increase on earnings announcement days and revert to their average levels two to five days later. The increase in betas is greater for...

This paper shows that the systematic risk (or "beta") of individual stocks increases by an economically and statistically signi…cant amount on days of firm-specific news announcements, and reverts to its average level two to five days later. We employ intra-daily data and recent advances in...

Recent studies in the empirical finance literature have reported evidence of two types of asymmetries in the joint distribution of stock returns. The Þrst is skewness in the distribution of individual stock returns, while the second is an asymmetry in the dependence between stocks: stock...

We study the accuracy of a wide variety of estimators of asset price variation constructed from high-frequency data (so-called "realized measures"), and compare them with a simple "realized variance" (RV) estimator.  In total, we consider almost 400 different estimators, applied to 11 years of...

This paper presents an overview of the literature on applications of copulas in the modelling of financial time series.  Copulas have been used both in multivariate time series analysis, where they are used to characterise the (conditional) cross-sectional dependence between individual time...

Forecast rationality under squared error loss implies various bounds on second moments of the data across forecast horizons. For example, the mean squared forecast error should be increasing in the horizon, and the mean squared forecast should be decreasing in the horizon. We propose rationality...

We investigate whether stock betas vary with the release of firm-specific news. Using daily firm-level betas estimated from intraday prices, we find that betas increase on earnings announcement days and revert to their average levels two to five days later. The increase in betas is greater for...