CNET

Despite repeated assertions to the contrary, Facebook finally admitted Wednesday that its youngest users really are losing interest in the social network.

In its third-quarter earnings call with analysts, CFO David Ebersman addressed the matter of Facebook's teen appeal with the company's most candid admission to date.

"Our best analysis on youth engagement in the US reveals that usage of Facebook among US teens overall was stable from Q2 to Q3, but we did see a decrease in daily users, specifically among younger teens," he said.

Facebook, Ebersman said, doesn't have an entirely accurate way to measure teen activity as the audience is known to fudge birth dates, but the company has developed internal metrics to look at teen usage.

The reveal, which contradicts past statements from CEO Mark Zuckerberg and other executives, confirms the anecdotal: Teens are tiring of Facebook.

The good news is that Facebook had a stellar third quarter punctuated by an impressive overall engagement rate -- the ratio of daily active users to monthly active users -- of more than 61 percent. The company had $2.02 billion in revenue and made 49 percent of its advertising revenue from mobile products.

Unfortunately, the disconcerting drop in teens as daily active users, a representation of the group's dip in engagement, has rattled investors who initially drove the company's stock up by as much as 16 percent in after-hours trading. At the time of publication, Facebook is trading at just under $49 per share, or right around its Wednesday close price.

Update, 3:10 p.m. PT: Facebook's stock has dropped 2 percent to $48 a share.