If Porsche becomes Volkswagen‘s largest shareholder, just five families will control sales of more than half the new cars in Europe, according to Automotive News Europe.

Ferdinand Porsche. Armand Peugeot. Henry Ford. Giovanni Agnelli. Herbert Quandt. The first three names are indelibly linked to the modern companies.

But without Agnelli there likely would be no Fiat. Without Quandt, BMW probably would have been absorbed by Mercedes-Benz.

The descendants of these five pioneers collectively own the controlling shares in huge corporations. The founding families no longer run most auto manufacturers a century and a quarter after the car was invented.

These five families remain. In a world of publicly owned corporations, they have traded full ownership to raise capital or acquire other brands. But they retain control. They allocate extra voting rights to their shares, build coalitions of shareholders, create holding companies to prevent dilution by generation – and sometimes they reinvest.

The families universally argue that their long-term ownership perspective builds value and permits better strategic decisions than short-term investors would make. The families say their anti-takeover tactics are necessary. Even though non-family professional managers often run the companies, the five families exert strong control. Few company boards flout the wishes of the largest shareholder.

And if the heirs who control all the voting rights at Porsche can parlay a 20% stake in Volkswagen into de facto control, only five families will hold the majority of European car sales.

Here’s the math for 2004, when western European sales were 14,851,191 million units. The combined sales of PSA/Peugeot-Citroen, BMW group, Fiat group, Ford group plus Mazda – and Porsche – were 5,776,044 units, a 38.89% market share. But add Volkswagen group’s 2,668,542 sales and the total is 8,444,586, or 56.86%.

Family ownership can be a rare corporate example of inter-generational decision making, analysts say.

“A family with a significant stake in an automaker can make a decision that won’t bear fruit for 10 years even with short-term shareholder sacrifice,” said one analyst. “An ordinary CEO wouldn’t want to make shareholders unhappy.”