Since 2023, when Rupert Murdoch launched an attempt to change his family's trust and give control of his media empire to his eldest son, the annual net incomes of Fox Corp and News Corp have grown by $2 billion and $79 million, respectively. This week, Murdoch's wishes were rebuffed by a court in Nevada.

So what? Family-owned businesses might be good for business. But good for families? The jury's out. The list of dynasties recently embroiled in costly legal disputes over succession and commercial control is lengthy and includes the household names of Murdoch, Agnelli (Fiat), Ambani (Reliance) and Redstone (Viacom).

The scripts write themselves. As Jesse Armstong, creator of HBO's Succession has said, you don't need to have talked with James Murdoch or Shari Redstone to taste the acrimony. Just "look at what their PRs are saying everyday about each other. It's all there, it's no secret".

The business case. Having "skin in the game" does, however, seem to reap rewards.

By the numbers:

Investors generally view family businesses as capable long-term stewards. But every dynasty has its twilight. Data shows that shares in companies run by the first generation gain almost twice as much as those run by the fifth generation.

Preserving power. All family businesses face choices about org charts and ownership structure. Shares are typically dual-class, allowing family members to hold outsize voting control - a perk they will often go to great lengths to retain (the Agnellis, for example, moved Exor's headquarters from Milan to Amsterdam, where vote structures are more flexible).

Bridget Kustin, an economic anthropologist at Oxford's Saïd Business School, has identified three main approaches to family ownership: autocratic, bureaucratic and democratic (the examples are Tortoise's).

What's more... In his annual letter to shareholders the revered investor Warren Buffett offered family businesses a simple piece of advice: "When your children are mature, have them read your will before you sign it," he wrote. "You don't want your children asking 'Why?'... when you are no longer able to respond."

As another episode in the Murdoch saga begins, it's not just his children asking that question.