Porsche SE, Volkswagen’s biggest shareholder, said it plans to scoop up 25 percent, plus one extra share, in carmaker Porsche AG voting stock when VW lists the sports car brand, possibly by the end of September, in what could be one of the world’s largest listings.

Investment fund Porsche SE is majority-owned by the family of the brand’s founder, the original VW Beetle’s designer. The shares acquisition would give the controlling Porsche and Piech families a blocking minority. In 2007, Porsche tried to take over the much larger Volkswagen but was forced to back away due to loan difficulties after the financial crisis. Then Volkswagen acquired Porsche AG in 2012. Securing a blocking minority would return some control over the carmaker to the family.

Meanwhile, the initial public offering would bring more financing for VW to assume a leading role in electric vehicle manufacturing and for autonomous driving and battery-development investments.