FRANKFURT/DUESSELDORF (Reuters) - Uniper said on Wednesday nothing was off limits in fresh talks with Finland’s Fortum, its top shareholder, renewing investor hopes for a full takeover of the 9.7 billion euro ($11.1 billion) German energy group.

A logo of German energy utility company Uniper SE is pictured in the company's headquarter in Duesseldorf, Germany, March 8, 2018. REUTERS/Thilo Schmuelgen

The comments seem to break a deadlock between the two groups ever since Fortum bought a 47 percent stake in Uniper from E.ON last year in a deal that included a full takeover bid and was seen as hostile by Uniper’s management.

Fortum last week said it had raised its stake to 49.99 percent, the maximum it is allowed to own after Russian authorities capped its ownership of Uniper at 50 percent due to a water license its Russian unit Unipro holds.

Uniper said late on Tuesday that its chief executive and finance chief, who both openly opposed Fortum’s takeover plan, would step down in August, adding the group’s remaining board members would soon start talks with Fortum in a working group.

“The outcome is completely open,” Uniper Chairman Bernhard Reutersberg told analysts on a conference call, adding talks were not expected to produce substantial results before Uniper’s annual general meeting scheduled for May 22.

Reutersberg said the aim of the talks, in which Uniper will be represented by Chief Commercial Officer Keith Martin and Chief Operating Officer Eckhardt Ruemmler, was to determine how a partnership between the groups could add value.

“This revives takeover speculation. A Fortum-friendly management could pave the way for a complete takeover and should try to find a solution for the current Russian blockade,” said a Frankfurt-based trader.

JP Morgan analysts were more cautious.

“We would caution investors who may think that this is a sign of Fortum getting close to reaching domination agreement any sooner,” they said in a note.

Shares in Uniper, which are up 16 percent year-to-date, rose as much as 3.2 percent and were 0.3 percent higher at 1107 GMT.

Uniper CEO Klaus Schaefer, who has been undergoing cancer treatment since last summer, said he could not devote the required energy to working out a cooperation deal with Fortum due to his illness.

Sources told Reuters in December that Fortum held talks with activist fund Elliott, Uniper’s second-largest shareholder with a 17.84 percent stake, over how to gain control of the German firm.

Elliott may raise its stake further, a person familiar with the matter said, a move that would make it harder for Fortum to gain full control without paying up.

“It is in the interest of everybody that we rapidly advance now to create value for the stakeholders of both companies,” Fortum CEO Pekka Lundmark said.

($1 = 0.8778 euros)