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FRANKFURT/LONDON, Oct 20 (Reuters) - Morgan Stanley's infrastructure investment arm is weighing a sale of a 40% stake in German wind and solar power project developer PNE AG after being approached by potential suitors, three people familiar with the matter said.

PNE confirmed on Thursday that Morgan Stanley and Photon Management intend to enter into open-ended preliminary talks with potential interested parties regarding Photon's stake in PNE. Photon, which is controlled by Morgan Stanley, is PNE's largest shareholder.

Morgan Stanley Infrastructure Partners (MSIP) acquired the PNE stake following a failed takeover attempt in 2020. Since then, PNE's shares have risen nearly five-fold, driven by global appetite for renewable energy assets.

PNE, which has a project pipeline of more than 9 gigawatt and a generation portfolio worth 261 megawatt, has a current market capitalisation of 1.4 billion euros ($1.38 billion), valuing Morgan Stanley's stake at 560 million euros.

The stake may attract interest from parties including French utility Engie and Sweden-based private equity firm EQT, the people said, adding that deliberations were at an early stage and that there was no certainty a deal will happen.

Engie and EQT declined to comment.

Buying the whole stake would trigger a mandatory takeover bid for all of PNE under German stock market rules.

"The Board of Management of PNE AG will support the intended preliminary discussions to the extent permitted by law and in the interest of the Company," the statement said.

A potential sale of MSIP's participation would result in chunky profits given the investment bank bought in at 4.00 euros per share and saw PNE's value grow to 18.50 euros.

News about the potential stake comes in the wake of major renewables deal in recent weeks, including RWE's $6.8 billion purchase of Con Edison's cleantech unit and BP's $4.1 billion takeover of U.S. biogas producer Archaea . ($1 = 1.0175 euros) (Reporting by Christoph Steitz, Andres Gonzalez and Emma-Victoria Farr; Additional reporting by Benjamin Mallet; Editing by Susan Fenton and Josie Kao)