Innogy saw its stock jump 16 percent in pre-market trade on Monday after parent RWE and rival E.ON announced plans to divide up the operations of Germany's largest energy company by market value.
The plans, announced on Sunday, are part of sweeping changes by utilities as they look to bolster green energy and prepare for Germany's exit from nuclear power in 2022.
They come just two years after RWE spun off renewable, retail and network operations to form Innogy and E.ON split off some of its business to create Uniper.
Shares in Innogy were indicated to open 16 percent higher in pre-market trade. RWE, which owns 76.8 percent of Innogy, was indicated 8 percent higher and E.ON was seen up 6 percent.
As part of Sunday's deal, E.ON plans to launch a 40-euro-per-share, or 5.2 billion euro ($6.4 billion), offer to Innogy's minority shareholders, a 16 percent premium to Friday's closing price.
"We believe that this development will be taken very positively as the market will see a 40 euros per share takeover offer as very likely for Innogy," Macquarie analysts said in a note, raising their rating to "outperform" from "neutral".
The deal, if approved, would spell the end for Innogy as a standalone company. The company, in turmoil since former Chief Executive Peter Terium resigned in December, on Monday announced plans to cut 400 million euros in costs through the end of 2020.
"We are making Innogy fit for future challenges, just like our customers, employees and shareholders expect us to. We will comment on the latest announcements by RWE AG and E.ON SE in due course," Innogy CEO Uwe Tigges said.
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.