You have to question whether or not Volkswagen and Porsche should have been one company from the beginning.  But post-WWII Germany was an organizational mess with agreements and treaties that carefully limited the activities and powers of German companies.

August 1, 2012, however, became a landmark day as Porsche and Volkswagen became one again.  The two companies have for years cooperated on design, development and manufacturing, the families that control each of the groups have had their spats and will probably continue to do so, but the two have finally found a way to become the Integrated Automotive Group of Volkswagen AG.

According to reports, a structure has been developed for Porsche SE to contribute its indirect 50.1% holding in Porsche AG to Volkswagen, making Volkswagen the 100% owner of Porsche.  Porsche has been assured of retaining its own identity as a unit of Volkswagen.