E.ON SE  (EONGY) shares surged to the top of the DAX index Wednesday after a report from Bloomberg said the German energy group was in talks to sell its stake in Uniper SE to Finland's Fortum Oyj (FOJCY) .

Uniper shares were also on the move, rising more than 3.6% to change hands at €17.27 each to value the hydroelectric-to-energy storage conglomerate at €6.327 billion. E.ON shares were marked 3.7% higher and trading at a year-to-date high of €7.85 each by 15:45 BST.

E.ON's chief financial officer, Marc Spieker, had said earlier this month that the group would move "swiftly" to sell its Uniper stake, but appeared to suggest that it would wait until next year when there we no longer tax restrictions on the disposal. E.ON listed Uniper in September 2016 but held on to a 46.65% stake in the group.

Earlier this week, Reuters reported that Goldman Sachs (GS - Get Report) had been hired by E.ON to look at options relating to a Uniper sale.

Uniper said earlier this month that its first quarter operating profits fell 41% to €514 million, beating analysts' estimates, thanks in part to a standalone payment from Russia's Gazprom, linked to a renegotiated gas supply contract in 2016, that wasn't repeated this year.