(Bloomberg) -- Polish billionaire Zygmunt Solorz ousted his two sons from his utility, deepening a family feud over control of his conglomerate, driving down valuations and raising concerns for a leading minority investor.

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Solorz’s investment vehicle, which controls Warsaw-listed power producer ZE PAK SA, voted out Tobias Solorz and Piotr Zak from the firm’s supervisory board at a shareholder meeting on Monday. The stock fell as much as 3.3% and is heading for its lowest closing level since 2022.

“We are very concerned about the current situation and the family conflict,” Szymon Ozog, chief executive officer of NN Group NV’s Polish pension fund, told Bloomberg. The fund owns 8.9% in ZE PAK, data compiled by Bloomberg show, making it the firm’s second-biggest minority shareholder.

The development comes amid uncertainty over Solorz’s empire, which besides power production also includes Cyfrowy Polsat SA, a media and mobile group. Last month, his children sent a letter to managers, voicing concern over alleged attempts to take over the firm, adding that they’re having difficulties contacting the billionaire due to his health and are in conflict with his current wife Justyna Kulka.

The 68-year-old billionaire briefly joined Monday’s ZE PAK shareholder meeting via video, sitting next to his lawyer at a undisclosed location. Solorz at times had trouble speaking clearly, with a participant in the shareholders’ meeting asking if he could repeat his comments. His lawyer was then heard telling Solorz to repeat his statement and pointing to a piece of paper from which the billionaire was reading.

‘Justified Concern’

The reshuffle in ZE PAK’s board comes a day before Cyfrowy Polsat SA are due to meeting, with the agenda also envisaging votes on board changes.

“There is justified concern for the health of Zygmunt Solorz,” NN’s Ozog said after the utility’s shareholder meeting. “Instead of focusing on strategy and development, the management boards’ attention will be focused on succession, personnel changes and determining who will actually control ZE PAK and Cyfrowy Polsat in the future.”

A spokesman for Solorz didn’t immediately respond to phone calls and text messages from Bloomberg News seeking comment.