FRANKFURT (Reuters) - German energy group Uniper (>> Uniper SE), subject to a takeover bid from Finnish peer Fortum (>> Fortum Oyj), on Thursday said it planned to pay about 310 million euros (£273.33 million) in dividends for 2018, a year-on-year increase of about a quarter.

In a strategy update, Uniper, in which activist investor Elliott Management earlier this week took a 5.32 percent stake, also said that dividends should increase by an average of 25 percent per year until 2020.

"Uniper has demonstrated outstanding performance on the stock market and presents a great opportunity for investors," Chief Financial Officer Christopher Delbrueck said. "Our shareholders will be able to share in this positive trend by continuing to earn significant dividends."

Uniper is opposed to Fortum's 22-euro-per-share offer, which runs until Jan. 16, saying it makes no strategic sense and significantly undervalues the company, whose shares closed at 25.80 euros apiece on Wednesday.

The group, which was spun off from former parent E.ON (>> E.ON) last year, also said it expects adjusted earnings before interest and tax (EBIT) of 0.8-1.1 billion euros next year, down from an expected 1.0-1.2 billion in 2017.

Shares in Uniper, which have more than doubled since their listing in September 2016, were indicated to open 0.3 percent higher in pre-market trade.

(Reporting by Christoph Steitz; Editing by Victoria Bryan)

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