One-time Finnish tech star Nokia (NOK -0.90%) has been hit hard by the coronavirus pandemic. Nokia stock has bounced back, however, gaining roughly 43% from mid-March to mid-April.

Today, investors learned that some of that rally might have been due to buying in a hostile takeover attempt. Nokia shares shot up more than 13% in early trading Thursday, and closed up 7.4%, following a report from online telecom journal TMT Finance that an unknown bidder was seeking to acquire parts or all of Nokia via a hostile takeover.

Cellphone reports a call from an unknown caller

Someone's ringing up Nokia -- but the company seems inclined to decline. Image source: Getty Images.

According to TMT, Nokia recently hired investment bank Citigroup to design a takeover defense. Bloomberg suggested KKR, Apollo Management, or Blackstone could be behind the attempt.  

The rumored takeover could value Nokia at approximately $17.4 billion, according to TMT.

That, however, is kind of a strange number for investors to be getting excited about. By close of trading Thursday, after all, Nokia had reached a market capitalization of $19.4 billion -- $2 billion above the reported takeout price. But even before Nokia began its rumor-fueled run-up, the stock was valued in excess of $18 billion -- which makes a $17.4 billion buyout bid seem rather cheap.

For its part, Nokia is keeping mum on the whole situation. Queried by Reuters for a comment, Nokia replied enigmatically, "Nokia does not comment on market rumors."