This study examines how the disclosure of negative sustainability-related incidents impacts the investment-related judgments of decision makers. Participants in a sequential 2x2 between-subjects experiment first received a company’s financial information, prior to viewing additional sustainability information (by the company and by a non-governmental organization (NGO); with and without negative disclosure). Results indicate that self-reporting of negative incidents does not affect decision makers’ stock price estimates and investment decisions compared to judgments based on financial information only. However, third-party disclosure of these incidents by an NGO negatively affects these investment-related judgments. Furthermore, the magnitude of the NGO reporting effect depends on whether the company itself simultaneously reports these incidents. Thus, disclosing negative incidents in sustainability reporting could lose some of its apparent stigma. Instead of avoiding negative reporting altogether, managers might use it as a risk mitigation tool in their reporting strategy. The results also emphasize the power of the often-mentioned NGO-“watchdog” function.