Facebook has banned the selling of administration rights for community groups.
This follows BBC News uncovering several incidents of group owners being approached about selling their pages.
Last month, nearly all 25,000 members of a west London group left in protest after finding out it had been sold by the person running it.
One buyer told BBC News they bought groups to promote their own business. They also sell unofficial ad space.
Facebook says the practice falls under the "spam" section of its Community Standards rules although there is no specific line that says this.
"We do not allow people to sell site privileges on Facebook, which includes selling admin roles or space on a page or group to display a third-party ad.
"We disabled the account reported to us by the BBC in November and urge our community to report cases like this so we can investigate and take swift action," a Facebook representative said.
Community groups are traditionally set up by Facebook members in the local area, acting in a voluntary capacity.
Members typically use them to discuss local issues, buy and sell unwanted items, and share upcoming events.
Jon Morter runs a local community group in his home county of Essex. It has about 30,000 members. He also belongs to one that is for other group administrators.
"A few weeks ago, a member posted to say someone had approached and offered to buy their group," he said.
"Another member then pointed out that they had been approached as well. Lots of us all dived in and realised it was the same bunch of people.
"We investigated [and found] that there are at least five, possibly more, local sales or community groups that this lot now own. They also say, 'If you want to put your advert on the banner, we'll charge you.'"
BBC News contacted someone in the UK who buys local groups.
They said they did so in order to showcase their own business and allow it "exclusivity" but added that group members were also allowed to promote their own companies, free, in their posts.
Other businesses were also invited to buy promotion by sponsoring the group's cover photo - the large photo at the top of each page - but not many did, the buyer said.
Mr Morter said administrators should not make money out of groups.
"You do it for the love of where you live. I'm proud of my town," he said.
Mr Morter also runs various music group fan pages and says that back in 2014 he was offered $4,000 (£3,100) from a US company to hand over the rights to one of them.
"They said they were part of a marketing company and 'we'd like to put our own advertisements on there but we wouldn't stop you putting your content on there still'. They wanted to control it."
He did not sell the page.
He said that he had read Facebook's Community Standards and could not see anything about whether or not the practice of buying and selling group rights was permitted.
"It's very vague - that's being polite about it," he said.
"There's not really anywhere specific where it says that you cannot purchase admin rights."
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