Hate speech on X dramatically increased during the several months that Elon Musk served as CEO when compared to the prior months, according to a new study. The analysis, published in the journal PLOS One Wednesday, showed that hate speech spiked on the platform shortly before Musk purchased X (then called Twitter), and continued through May 2023. Researchers found that the weekly rate of hate speech was up about 50% over the months prior to Musks purchase. The study noted an increase in use of homophobic, transphobic, and racist slurs.The researchers also found a spike in likes of hate posts, which they said indicate increased engagement. The findings run contrary to Musks claims that hate speech impressions on the platform were sloping downward. (X did not respond to Fast Companys request for comment.)To be sure, the researchers said they could not set firm conclusions on a cause-effect relationship between Musks acquisition of X and the findings. Still, they argued for stronger moderation and more research. Overall, these results highlight a need for increased moderation to combat hate and inauthentic accounts on X, the researchers wrote. Once Musk took over the social media company, he quickly loosened restrictions on what can be said or shared on the platform.The studys release coincides with the slow return of many high-profile advertisers to X. Several brands, including Comcast, Apple, IBM, Disney, and Warner Bros., pulled their ad spend from the platform soon after Musks takeover, because ads began to appear next to hate speech and other offensive content. But now Musk is one of the top officials in President Trumps administration, and some may want to bolster their relationships with Musk. Apple is reportedly considering returning to the platform. Comcast, IBM, Disney, and Warner Bros. have all resumed ad spend, according to The Wall Street Journal.Still, ad buyers have said that brands that return to X are spending much less than they were before Musk acquired the company. (Amazon is reportedly upping its ad spend.)