With the increase in the number of small investors in the Brazilian stock market, public information increases its influence over expectations and, consequently, over the value of determined stocks traded in this market. In this context, an event study can identify irregularities caused by imperfections in the dissemination of information, and their effects on the stock market. This project analyzes, using an event study, the impact of articles published on the front page of the Valor Econômico newspaper on the value of the stocks involved in those articles. The comparison of the returns of those stocks before and after the event was performed, aiming at identifying biases that could demonstrate or not the strength of the information issued.