This article discusses the issue of applying trade defense measures in oligopolized or monopolized markets, addressing the recent integration of the trade defense investigation body with the public interest area in Brazil. By analyzing two recent cases of plasterboard and grinding bodies, I raise the possibility of complementing antitrust analysis with trade defense. I conclude that it is necessary to have greater convergence between investigations of unfair trade practices and concerns about maintaining a competitively healthy market. I also argue for the importance of institutional restructuring of the new system of trade defense and public interest by separating damage investigation and causal link analysis, thus creating an exempt court that allows further discussion regarding antitrust and anti-dumping cases.