Even though Volkswagen (VW) owns cars like Porsche and others, it should be mentioned that Porsche SE controls and owns majority in VW.
But technically Audi owns the whole group. VW doesn't plan and design the engines, gearboxes and cars, Audi does. VW is more a logistics and SW company now, just with a big brand name, with the cheaper "Audis" labelled as VW.
Porsche cars are made by Porsche AG which is a subsidiary of Volkswagen AG - Porsche SE then holding a controlling stake in Volkswagen AG.