LinkedIn falls hard on weak forecast

LinkedIn shares plunged more than 40 percent on Friday after a weak outlook from the career-focused social network fueled fears of a slowdown.

The shares plunged 43 percent to $109.57 at 1900 GMT.

LinkedIn reported a loss of $166 million for 2015, far wider than the $16 million deficit for 2014.

But investors were unsettled by the weak outlook of revenues well below the $3.9 billion expected.

The outlook "implies material deceleration in growth, which removes support for the company's historically premium valuation," said Mark Mahaney at RBC Capital Markets in a research note.

Barclays analyst Paul Vogel said he was not surprised by the sharp reaction in LinkedIn stock.

"It is definitely a lot harder not to wonder if the company is starting to hit saturation levels with certain users or enterprises," he said in a note to clients.

LinkedIn claimed 414 million users in December, up by 18 million from the previous quarter and 67 million over the past year.