HELSINKI (Reuters) - Finland's largest utility Fortum (>> Fortum Oyj) is in advance talks to buy German utility E.ON's (>> E.ON) 46.7 percent stake in nuclear and fossil energy group Uniper (>> Uniper SE) for 3.76 billion euros (£3.33 billion), the companies said on Wednesday.

Fortum is preparing to make a voluntary offer of 22 euros ($26) per share to all Uniper shareholders in early 2018, it said in a statement.

Shares in Fortum rose 5 percent while those in Uniper and E.ON were up 4.3 percent and 2.4 percent, respectively.

(Reporting by Tuomas Forsell, editing by Jussi Rosendahl)

Stocks treated in this article : Fortum Oyj, E.ON, Uniper SE