Allen Tran, trader and founder of the Facebook, Inc. (NASDAQ:FB) discussion group Robinhood Stock Traders, claims his group has been shadowbanned on Facebook for more than a month and is one of several large trading groups that have been negatively impacted by changes to how these groups are treated by Facebook’s search algorithm.

Multiple Bans: Tran’s group has more than 160,000 members, and he first ran into problems with Facebook back in January when his group was banned for being a “dangerous organization.” Upon Tran’s appeal, Facebook reinstated the group.

Tran’s next run-in with Facebook happened on Jan. 27 during the height of the WallStreetBets-fueled GameStop Corp. (NYSE:GME) trading frenzy.

Tran’s group was banned a second time, this time for violating policies related to “adult sexual exploitation.” Once again, Tran said Facebook’s ban notice did not provide any specific evidence of the content allegedly violating its policies. Tran told Benzinga no such content ever existed.

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Shadow Ban: The second ban was once again lifted after Tran appealed, but he says the group remains shadowbanned to this day.

Shadowbanning is a way of blocking easy access to content on social media platforms without banning the content outright. Benzinga confirmed that Tran’s group is not currently among the top search results for “Robinhood Stock Traders.” However, clicking on a direct link to the group confirmed Facebook has not blocked direct access to the group.

Tran showed Benzinga a correspondence he had with a Facebook representative on Feb. 26 in which the representative denied Tran’s group had been shadowbanned. The representative also told Allen his group was a “unique case” and Facebook had a “special team looking into your group.” Five weeks later, Allen said nothing has changed and he has received no further update on the situation.

A Facebook representative did not immediately respond to Benzinga’s request for comment.

“Something is happening across all of these stock trading groups on Facebook right now, and we are the only ones who know it’s happening,” Tran told Benzinga.

In addition to his group, Tran said he has observed sharp declines in growth for other popular Facebook trading groups as well.

“There is no natural flow right now coming from Facebook. They’re just shoving us down in the algorithm.”