Facebook (FB) is advancing today after the stock hovered near its 2013 lows in recent days. ANALYST REACTION: In a note to clients earlier today, JPMorgan analyst Doug Anmuth wrote that investors have been worried that Facebook could be losing market share to other websites such as Twitter and WhatsApp. But competing services are having only a minimal impact on Facebook, and usage of Facebook has remained steady, according to Anmuth. Consequently the analyst believes that fears about Facebook's competition are overdone, and he recommends buying the stock. TODAY'S PRICE ACTION: In mid-morning trading, Facebook gained 63c, or 2.50%, to $26.