We have carried out an event study to investigate stock returns associated with the announcement of equity issues by Brazilian firms between 1992 and 2003 in order to determine market reaction before, during, and after the issue announcement. After measuring abnormal returns by OLS, we used ARCH and GARCH models over 70% of the sample. Our results are remarkably consistent with most of the international empirical literature. Some previous empirical findings have turned up abnormal returns before the announcement date, interpreted as signs of insider information. This evidence also appears in our study as we found an average cumulative abnormal return of -0.01 three weeks before the announcement. With respect to the announcement date, the evidence reported in the literature is virtually unanimous in showing negative abnormal returns, meaning that stock issues convey pessimistic information to the market. Our study confirms these findings with an average -0.03 cumulative abnormal return on the first three days following the announcement. Finally, the empirical literature has also collected evidence of long-term negative abnormal returns after the issues, which we also confirm, with an abnormal return of -0.28 after one year following the announcement. The results also show that ARCH/GARCH estimation of abnormal returns is superior to OLS estimation.
Brazilian stock market; SEOs; event study; market volatility; GARCH
