This requires a good investigative journalist with good understanding of economics. Which I am not. I could tell you some names for Slovakia (J&T, Penta, Brhel, Výboh), which probably you would have no way to verify. (Note that the last one doesn't even have a Wikipedia page. These people in general prefer privacy, they own most of the media, and they have a lot of money to sue you if you write something negative about them, and they also own the judges which means they will win each lawsuit.)

I am not even sure if countries other than ex-communist use this specific model. (This doesn't mean I believe that the West is completely fair. More likely the methods of "power above politicians" in the West are more sophisticated, while in the East sophistication was never necessary if you had the power -- you usually don't have to go far beyond "the former secret service bosses" and check if any of them owns a huge economical empire.)