Abstract There has been a significant growth of social media as a means to inform oneself about politics. This article explores the consequences of this trend on the credibility audiences attribute to news exposing corrupt politicians and on their willingness to penalize the exposed politicians in elections. The study focuses on ten Latin American cities and employs a randomized control trial using experimental data embedded in a survey. Through this method, credibility and penalization levels are compared between state communications, newspapers, named journalists on social media, and anonymous journalists on social media. The article’s key findings demonstrate that corruption reports published on social media are deemed less credible than those published by state auditors and newspapers. This effect is exacerbated when the source of the report is anonymous. In addition, reports on corruption published on social media by anonymous sources have a negative effect on voter penalization of corrupt politicians.