President Barack Obama participates in a LinkedIn Town Hall meeting with LinkedIn CEO Jeff Weiner in Mountain View, Calif. The company launched their IPO in May and posted a loss for the third quarter as the company spent money to expand. Reuters/Jason Reed

Shares of LinkedIn Corp. (Nasdaq: LNKD), one of the top professional social network sites, rose as much as 1 percent in early trading despite reports of security breaches of as many as 6.5 million member passwords.

In early trading, LinkedIn shares rose as high as $94.10 before dropping back to $94, up 92 cents at midday. The Mountain View, Calif.-based site is being probed by Ireland's data protection commissioner about the breaches.

The company hasn't made a formal announcement or response. In its most recent report, LinkedIn claimed having as many as 161 million members, with about 60 percent outside the U.S.

Private, of San Diego, was also apparently hacked. The online dating service has about 20 million users. It said it had notified members of the breaches.

About 8 million passwords for the two sites were apparently hacked and posted by someone using the monicker dwdm, who has not been further identified.

LinkedIn executives may be expected to say more about the breach at the company's June 14 annual meeting in Santa Clara, Calif.