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Investing.com - Twitter plunged in midday trading after a blistering note from Citron Research called the stock “toxic” to investors and advertisers.

Twitter (NYSE: ) tumbled about 13%.

In a note released today entitled “Twitter has become the Harvey Weinstein of Social Media,” Citron laid out its case for Twitter’s vulnerabilities and slapped a $20 price tag on shares.

“Amnesty International has concluded that Twitter is an abuser of human rights and has become a place that is ‘toxic’ for women, noting that women are abused every 30 seconds on Twitter,” Citron wrote. “The study focused on 800 female journalists and politicians to show the culture of hate that underpins Twitter.”

“Citron has been following Twitter for years and when we read the just published piece from Amnesty International, we immediately knew the stock had become uninvestable and advertisers will soon be forced to take a hard look at all sponsorships with Twitter,” it said.

With Facebook (NASDAQ: ) down 25% in three months on privacy and management integrity concerns, “if you dislike Facebook you must absolutely HATE Twitter,” Citron said.

The index was down about 2% midday.

Netflix (NASDAQ: ) was off about 4.8% and Facebook fell about 1%.