Insider Information and its Effect on Prices of Two Ways of Stock Issues at Bovespa

Abstract

The event study was used to analyze the reaction of market prices to the announcement of two ways of seasoned equity offerings: broad offerings and restricted offerings to stockholders, in firms listed at Bovespa. The market price reaction was analyzed before, during and up to one year after the announcement dates, considering issues between 1995 and 2005. Two standard methodologies were used to measure the abnormal returns. For the model of returns adjusted to market the results did not shown significant difference for the two ways of issues (except for the negative returns in the long time by the broad public issues). In the model of returns adjusted to risk and market, the stocks with heteroscedasticity in the residuals (46% of the sample) had its coefficients replaced by auto regressive models. In this case, the results for broad offerings showed that (a) there are evidences of insider information before the announcement date, (b) negative abnormal returns in the announcement date, and (c) negative returns up to one year after the issues; and for restricted offerings, the results were not significant, demonstrating that in this case the information asymmetry and insider information problems are less important.