Impacto ambiental e retorno acionário de companhias listadas na BM&FBOVESPA
Resumo
This study aimed to analyze if the information from an
environmental incident causes impact on stock prices of
the companies responsible, indirectly analyzing the loss
of informational efficiency semi-strong level. For this, the
event studies methodology was used together with a
bootstrap simulation. Data from daily prices of assets
were collected from Bloomberg® software and the news
of environmental disasters were collected in newspaper
advertisements. The events are summarized in the
mining and oil sector companies listed on BM&FBovespa.
The results suggest evidence of loss of efficiency for
events in general, and that share prices suffered falling
within 4 days after the event. Thus market efficiency did
not behaved semi-strong form, the delay in the
incorporation of this information. Our research suggests
a need for increased credibility in the dissemination of
information to the market, as investors cautiously
observe the effects of these events in stock prices.