Plans to break up Innogy and divide its assets between parent RWE and E.ON, first announced a day earlier, added 4.3 billion euros to the market value of Germany's three largest utilities in the sector's largest overhaul in recent history.

Germany's power companies are reshaping as they look to boost green energy output, shift away from fossil fuels and prepare for Germany's exit from nuclear power in 2022.

"This strategic exchange of businesses will create two highly focused companies that will shape a better future for Europe's energy landscape," E.ON Chief Executive Johannes Teyssen said in a statement.

"Each company will have a stronger entrepreneurial core."

The changes will turn RWE into Europe's third-largest renewable player and at the same time create one of the continent's top grid and energy retail groups under the aegis of E.ON, with about 50 million customers across the continent.

"Overall, we view the planned transaction between RWE AG and E.ON SE as positive, from a strategic as well as a financial point of view," municipal shareholders in RWE, which together hold about 23 percent in the group, said.

"We think that this transaction gives significant thrust to the successful implementation of Germany's energy shift."

RIVAL BID UNLIKELY

Before striking a deal with E.ON, RWE held talks with European peers Enel and Engie and came close to a deal with Spain's Iberdrola before Christmas, people familiar with the matter said.

Shares in Innogy closed up 12.1 percent at 38.70 euros after Sunday's proposed deal from RWE and E.ON, which plans to offer Innogy's minority shareholders 40 euros per share, or 5.2 billion euros, a 16 percent premium to Friday's close.

Two bankers who have worked on previous Innogy deals put the chances of a rival bid for the German energy company as "very low" to "zero", since RWE has already explored alternative deals with other candidates.

RWE is being advised by Bank of America Merrill Lynch and Citi on the deal, E.ON has hired Perella Weinberg Partners and BNP. Goldman Sachs is working for Innogy, sources said. The deal is expected to close in late 2019.

In a letter to staff seen by Reuters, Innogy interim Chief Executive Uwe Tigges said Innogy's management and supervisory boards would thoroughly assess the planned deal, which was agreed in principle and still requires antitrust approval.

"We assure you that the interests of the employees of our company as well as those of our shareholders continue to be our primary focus," said Tigges, who has been in the role for only three months.

Innogy, which reported its annual results on Monday, said that it had so far not reflected on the proposal and would comment at a later stage.

SYNERGIES

Frank Bsirske, head of the Verdi labour union and deputy chairman of RWE's supervisory board, welcomed the deal, saying it offered good prospects for growth and jobs. The supervisory boards of both RWE and E.ON have approved the transaction.

Germany's cartel office said it was too early to comment on possible hurdles in the planned asset swap deal, which is expected to involve German and European antitrust regulators.

Innogy and E.ON have large overlapping retail businesses in Germany, Britain and the Czech Republic. E.ON said it expects 600-800 million euros in annual synergies by 2022.

Shares in RWE, which owns 76.8 percent of Innogy, closed 9.2 percent higher while E.ON's ended the day up 5.4 percent. Their proposed transaction comes just two years after RWE spun off its renewable, retail and network operations to form Innogy and E.ON split off some of its business to create Uniper.

If approved, the deal would spell the end for Innogy as a standalone company. It has been in turmoil since former Chief Executive Peter Terium resigned in December and on Monday said it would cut 400 million euros in costs through the end of 2020.

Analysts at Jefferies said while helping E.ON achieve scale and efficiencies in networks and retail, and transforming RWE into a leading renewables and security of supply provider, a deal "would involve another two years in costly restructuring".

Innogy reported a 3 percent rise in 2017 adjusted operating profit and said it would propose a dividend of 1.60 euros per share for 2017, unchanged from a year earlier.

E.ON, in a separate statement on its annual results, said it would propose a dividend of 0.30 euros per share for 2017 and 0.43 euros per share for 2018.

(Additional reporting by Arno Schuetze in Frankfurt, Dasha Afanasieva in London, Vera Eckert in Essen and Anneli Palmen in Duesseldorf; Editing by Alexander Smith, Keith Weir and David Evans)

By Christoph Steitz and Tom Käckenhoff

Stocks treated in this article : Engie, Enel, Iberdrola, RWE, E.ON, innogy SE