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 2007-2009 were suddenly public.
However, Facebook told the BBC: "[The] messages were older wall posts that had always been visible on the users' profile pages.
Separately, Facebook shares fell up to 11% after an influential journal said the stock is worth just $15.