A rumour that Facebook users' private messages were appearing on public timelines is false, the firm has said.
Some users, mostly in France, reported that "private messages" sent between 2007, 2008 and 2009 were suddenly public.
According to the BBC, Facebook said the messages were older wall posts that had always been visible on the users' profile pages.
In addition, the social network said: "Facebook is satisfied that there has been no breach of user privacy."
A source at the company told the BBC that engineers said there was "no way" the two areas of data could get mixed up.
The source said that "no mechanism" had ever been created that would allow a private message to be published onto a user's wall or timeline.
Similar rumours surfaced and were investigated in 2011, the source said, but after "extensive investigation" they were proven to be untrue.
Despite Facebook's statement, many users reported finding what they believed to be old private material.
Meanwhile, Facebook shares were under pressure after the US financial publication Barron's said the stock is worth perhaps only $15 a share, well below the $38-a-share flotation price.