This paper proposes a new approach to control the effects of time-varying parameters on the estimates of abnormal returns. Event studies usually assume that the parameters of the market model are stable. Using a sample of firm takeovers, however, I find that this assumption is indeed rejected....

Starting from the Cholesky-GARCH model, recently proposed by Darolles, Francq, and Laurent (2018), the paper introduces the Block-Cholesky GARCH (BC-GARCH). This new model adapts in a natural way to the asset pricing framework. After deriving conditions for stationarity, uniform invertibility...

We compare the beta model (a.k.a. covariance model) and the characteristics model in terms of their ability to reduce portfolio risk. When global-minimum-variance portfolios (GMVPs) are constructed out of the 500 largest US stocks for the 30-year period between 1981 and 2011, the...

The existence of a premium to momentum portfolios, formed by buying recent winners and selling recent losers is widely accepted, although the source of the returns remains controversial. It remains a focus of behavioural finance. We focus on one set of explanations, based on prospect theory,...

In Cascon and Shadwick (2006) we extensively discussed the use of models in finance. We pointed out how ideas that have become generally accepted often depend on assumptions that, as time passes, are likely to be unstated or even forgotten entirely, with potentially significant consequences. In...

Using a framework akin to portfolio theory in asset pricing, we introduce the concept of “political beta” to model firm-level export diversification in response to global political risk. The main implication of our model is that a firm is less responsive to changes in political relations...