Stock price reaction to profit warnings: The role of time-varying betas

This study investigates the role of time-varying betas, event-induced variance and conditional heteroskedasticity in the estimation of abnormal returns around important news announcements. Our analysis is based on the stock price reaction to profit warnings issued by a sample of firms listed on the Hong Kong Stock Exchange. The standard event study methodology indicates the presence of price reversal patterns following both positive and negative warnings. However, incorporating time-varying betas, event-induced variance and conditional heteroskedasticity in the modelling process results in post-negative-warning price patterns that are consistent with the predictions of the efficient market hypothesis. These adjustments also cause the statistical significance of some post-positive-warning cumulative abnormal returns to disappear and their magnitude to drop to an extent that minor transaction costs would eliminate the profitability of the contrarian strategy

An empirical test of 'put call parity'

In this article, we examined the validity of 'Put Call Parity' (PCP) in the Israeli stock market. Estimating the parameters for the PCP equation, we reject the validity of PCP with a 100% confidence level. The estimated PCP equation includes a significant intercept that points to the possibility of having arbitrage opportunities. Measuring the profit rate for portfolios that include options with various exercise prices, we find a potential profit of about 3%-3.4% in all cases.put call parity, arbitrage,

Sixty years of research leadership: contributing authors and institutions to the journal of finance

Leading authors, Leading institution, Research leadership, G00, N0,