Nokia Oyj shares jumped over 10 percent on Monday as Google Inc's offer for Motorola Mobility Holdings rekindled speculation of a bid for the Finnish mobile phone company.

Nokia's shares have fallen around 45 percent since the start of the year, prompting some speculation the stock could be getting cheap enough to tempt a bidder. The company, once the leader in smartphones, has been losing market share in both high-end devices and cheaper phones.

Google said it was paying around $12.5 billion in cash, or $40 per share, a 63 percent premium to Motorola Mobility's closing price on Friday.

This price should ring bells on how low Nokia shares currently are. And if you think of patents, now Nokia is the one with a really strong patent portfolio, said Swedbank analyst Jari Honko. I'd expect this will boost the speculation whether Nokia would be a takeover target too.

One Swiss-based trader said the Google deal gave Nokia shares a huge sentiment boost.

Nokia shares were up 10.5 percent at 4.14 euros by 1410 GMT, having risen as high as 4.28 euros.

Nokia's market capitalization as of last Friday was 14 billion dollars. Applying the premium being offered Motorola Mobility, without any consideration for debt, would value Nokia at over 23 billion euros ($32 billion).

Both Microsoft Corp, which is partnering with Nokia for its new phones, and Samsung Electronics, have been mentioned as possible buyers.

Nokia did not comment on the buyout rumors, but said a deal between Google and Motorola could help its own partnership with Microsoft. Nokia decided earlier this year to go with Windows instead of its own MeeGo software, which is being phased out.

This could prove to be a massive catalyst for the Windows Phone ecosystem, Nokia spokesman James Etheridge said in an e-mail. He also said that both Nokia and Microsoft were cooperating with their respective intellectual property portfolios.

Nokia is pinning its turnaround hopes on the new Windows-based phones due later this year, although some analysts have said it may be losing so much market share in the meantime that it may never be able to recover.

J.P. Morgan analyst Rod Hall said in a note to clients that Nokia as well as BlackBerry maker Research in Motion could benefit from potential confusion and competition among phone makers using Google's Android software.

In our opinion, this favors both RIMM and Nokia. We also would now expect Nokia takeover speculation to increase, he said, noting Nokia's large number of patents.

(Reporting by Ritsuko Ando and Jussi Rosendahl; Editing by David Holmes and David Cowell)

Motorola