LinkedIn Corp., owner of the world's biggest professional-networking website, said that it's looking into unconfirmed reports of stolen passwords.

“Our team continues to investigate, but at this time, we're still unable to confirm that any security breach has occurred,” the Mountain View, California-based company said on its Twitter Inc. micro-blogging site.

LinkedIn sent its first tweet this morning telling users that it was looking into the issue and followed up at about 11:20 a.m., New York time, saying nothing was confirmed. A spokeswoman, Erin O'Harra, said LinkedIn will continue to update users on Twitter.

The company cites security issues as a risk for investors in regulatory filings. In a quarterly report to the U.S. Securities and Exchange Commission last month, LinkedIn said it has experienced website disruptions and outages for reasons that have included “denial of service or fraud or security attacks.” Future disruptions were possible, according to the filing.

While the company didn't mention any specific attacks, Reuters reported in May 2011 that the website had “security flaws” that made accounts vulnerable to hackers, citing a security researcher who identified the problem.

LinkedIn fell 1.4 percent to $91.74 at 12:20 p.m. in New York. The stock has more than doubled since the company's initial public offering in May 2011.

Bloomberg News

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