Facebook Shares Plummet Despite Profit Boost Facebook saw some $18bn (£11.2bn) wiped off its share price in minutes after a top exec admitted the social network had seen a drop in teenage users. The company's stock soared by around 18% to $57.98 (£36.16) in after-hours trading following the announcement of better-than-expected financial results. But the shares slid back to $48.44 (£30.20) - slightly below the day's closing price of $49.01 (£30.56) - during a conference call between Facebook management and market analysts. Investors may have been spooked by comments from finance chief David Ebersman, who said the social network had noted a decrease in daily use among the important demographic of younger teenagers. He said: "Our best analysis of youth engagement in the US reveals that usage of Facebook among US teens overall was stable." But he added: "We did see a decrease in daily users specifically among younger teens." Mr Ebersman said the trend was of "questionable statistical significance" but that he wanted to share it as the company was often asked about it. The statement comes after a survey by financial firm Piper Jaffray found earlier this month that Twitter had overtaken Facebook as the preferred social network for teenagers. Facebook's finance chief David Ebersman revealed the drop in teen users Facebook has dropped from being the top choice with 44% of young users a year ago to just 23% in the latest survey. The share price fluctuation masked an impressive set of Q3 figures that surpassed Wall Street's expectations. The company's revenue grew 60% to £2.02bn (£1.26bn) as its share of the mobile ad market continued to grow. The world's largest social network said it had earned $425m (£265m) in the third quarter - up from a loss of $59m (£37m) in the same period a year ago. Adjusted earnings were $621m (£387m) in the last quarter - better than analysts expected. Facebook's advertising revenue was $1.8bn (£1.12bn), up 66% from a year ago, with mobile ads accounting for 49% of the company's total ad revenue during the quarter. CEO Mark Zuckerberg said: "The strong results we achieved this quarter show that we're prepared for the next phase of our company, as we work to bring the next five billion people online and into the knowledge economy." Facebook went public in May 2012 at $38 per share but initially saw its share price tumble. It took the stock more than a year to surpass the launch price as the company worked to prove that it could grow mobile advertising revenue at a time when an increasing number of its users were accessing it on mobile phones and tablet computers.