Adds context to paragraph 1, adds CEO comments on deal in paragraphs 3-8, share placement in paragraph 10, background in paragraph 12

By Christoph Steitz and Tom Käckenhoff

FRANKFURT/DUESSELDORF, June 22 (Reuters) - RWE has raised its stake in power grid operator Amprion to a majority for €3.6 billion ($4.1 billion), Germany's biggest power producer said on Monday, betting on regulated assets in a push to make its business more resilient.

The deal will give RWE a pro rata stake of 55% in Germany's second-largest high-voltage power grid operator, exposing the company to more regulated returns at a time when its capital allocation has drawn scrutiny from some investors.

The deal will make regulated infrastructure the company's third business pillar, CEO Markus Krebber said, complementing renewables and gas-fired power generation, as the company seeks a more robust set-up.

Larger peers, including France's Engie ENGIE.PA, Italy's Enel ENEI.MI and Spain's Iberdrola IBE.MC, all have a sizeable regulated asset portfolio, something which Krebber said enabled more flexibility when it comes to investments.

'MORE ROBUST PORTFOLIO'

"We've always looked a bit to our peers in ... Southern Europe, the big players who have generation and grid operations, naturally," Krebber told journalists.

"They have a significantly more robust portfolio and greater flexibility when it comes to investment."

He said the deal, which is expected to close in the third quarter of 2026, would add €930 million of adjusted core profit from 2031, adding it would provide long-term stability in terms of returns at a time of changing market dynamics.

"At the moment, generation is clearly the absolute favourite given the data centre and AI boom," he said. "But let's think back 24 months – things were very different then."

RWE said the deal would be funded by issuing shares representing 10% of its capital, adding Qatar, already the German group's single biggest investor, as well as Norges Bank NOCB.UL, had already agreed to buy €1 billion worth of shares.

Shares were placed at €54, a 2.9% discount to Monday's closing price, resulting in gross proceeds of around €4 billion, RWE said.

Sources had told Reuters in February that major owners of Amprion were considering selling stakes to new investors in the face of growing funding needs for energy networks across Europe.

RWE last year formed a joint venture with Apollo Global Management APO.N for its existing 25.1% stake in Amprion.

($1 = 0.8750 euros)