Facebook's stock soared after the social networking company reported stronger-than-expected results for the fourth quarter, fueled by strong mobile advertising revenue.

Facebook, which turns 10 next week, said Wednesday that more than half of its advertising revenue now comes from mobile. That's a big milestone considering it only started showing mobile ads in 2012. Investors fretted at the time that it wouldn't be able to evolve into a "mobile-first" company. The quarter's results are a sign that it has.

Menlo Park, Calif.-based Facebook's stock rose $7.55, or 14 percent, to close at $61.08 in late afternoon trading. It hit a record high of $62.50 earlier.

At the end of 2013, more than three-quarters of Facebook's 1.23 billion users — 945 million — logged in using their mobile devices at least once a month.

Baird Equity analyst Colin Sebastian said key user metrics and engagement trends — that is, how much and how often people use Facebook — remain healthy. He noted that advertising revenue accelerated for the seventh consecutive quarter.

"Looking ahead, we expect further growth from video ads, Instagram, and global monetization," he wrote in a note to investors. The analyst has an "Outperform" rating on Facebook's stock. He raised his target price to $65 from $54 in light of the results.