Eficiência informacional em anúncios de criação de joint-ventures no mercado acionário brasileiro

This study aimed to verify the presence of semi-strong efficiency in the Brazilian stock market when the creation of joint ventures was announced. The period analyzed in the study was from May 24, 2012 to May 24, 2017, with a sample of 12 announcements about the creation of new joint ventures, in which at least one of the shareholders was a publicly traded Brazilian company. Subsequently, the event study methodology was employed. Expected returns were estimated using the market model, and then abnormal returns (AR) and cumulative abnormal return (CAR) were calculated during the event window. Finally, statistical tests were performed for the average of the abnormal returns in order to verify if the values were significant. The results of the work showed a strong downward trend in the ARs throughout the event window, consequently the CAR was strongly negative, reaching a value of -4.17% at the end of the event window. This fact indicates that the creation of a joint venture was seen as negative by the market. Regarding the statistical significance of the results, it is noteworthy that, only in the two days prior to the announcement of the creation of the joint venture, the AR was significant, in the other days the market behaved efficiently, with the AR not being statistically different from zero. The result of this research is relevant to the decision of managers who evaluate the possibility of establishing a new joint venture, showing the impacts that this decision may have on their company's stocks.