LinkedIn Corp. (LNKD), the biggest professional-networking site, forecast sales that fell short of analysts’ estimates, pushing the stock down as much as 15 percent, as growth slowed in all three of its businesses.

First-quarter revenue will be $455 million to $460 million, the Mountain View, California-based company said today in a statement. Analysts on average projected sales of $469.4 million, according to data compiled by Bloomberg.

LinkedIn, whose shares have soared almost fivefold since the company’s 2011 initial public offering, is contending with the challenges of reaching workers overseas and consumers’ shift to mobile devices. To try and reach more job seekers, LinkedIn said today that it acquired Bright Media Corp., an analytics company that helps match candidates with the right employers, for about $120 million in cash and stock.

“LinkedIn is continuing to grow, but that growth is slowing because of a scaling up of the business,” said Steve Weinstein, an analyst at ITG Investment Research. “As you get bigger, it gets harder and harder to find a lever that can be material to growing your business.”

The shares fell as much as 15 percent in extended trading to $191.13 after rising 4.2 percent to $223.45 at the close in New York.

Net income fell 67 percent in the fourth quarter to $3.78 million, or 3 cents a share, from $11.5 million, or 10 cents, a year earlier, the company said. Sales in the period jumped 47 percent to $447.2 million, exceeding the $437.6 million average analyst estimate, according to data compiled by Bloomberg.
Adding Users

Membership climbed 37 percent to 277 million from 202 million a year ago, when the number of users increased by 39 percent. Sales in talent solutions, LinkedIn’s main business, rose 53 percent to $245.6 million, compared with growth of 90 percent in the same period last year.

Revenue growth in LinkedIn’s advertising business, called marketing solutions, slowed to 36 percent from 68 percent a year earlier, while the premium subscriptions unit increased revenue by 48 percent, down from 79 percent in the same period last year.

It’s been a mixed quarter so far for the other top social-networking services. Twitter Inc. said yesterday that its user growth was slowing, pushing shares of the microblogging service down 24 percent. Facebook Inc. last week reported revenue that topped analysts’ estimates, with more than half of ad sales coming from mobile devices. The stock soared 14 percent after the announcement.
Global Competitors

In international markets, where LinkedIn faces competition from Viadeo in France and Xing in Germany, sales rose 54 percent to $176.1 million and accounted for 39 percent of revenue, up one percentage point from a year earlier.

LinkedIn said that 41 percent of traffic now comes from mobile devices, though the company didn’t disclose mobile revenue. Internet companies including Facebook and Google Inc. have invested heavily in capturing users as they move to smartphones and tablets even as sales have been slow to catch up.