LONG Volkswagen’s most reliable profit driver, luxury sports car maker Porsche has become its biggest problem, creating a road bump for chief executive officer (CEO) Oliver Blume’s restructuring plans at Europe’s biggest carmaker.

Less than four years after its record listing, Porsche has turned into a poster child for the broader group’s woes, dethroned in the once-lucrative Chinese market and bruised from costly missteps in the transition to electric.