Think fracking pioneer Harold Hamm’s divorce was pricey? Think again. The ex-wife of Russia’s richest man Vladimir Potanin wants half his $15 billion fortune.

The couple divorced last year. Potanin offered Natalia Potanina, his wife of 30 years, a settlement including a monthly allowance of $250,000 and properties in Moscow, London, and New York.

But she says that is only a fraction of what is rightfully hers. Natalia claims Potanin’s real wealth is held in offshore companies, and she’s launched an international legal battle to get hold of it.

Vladimir Potanin runs the world’s biggest nickel producer Norilsk Nickel. One of Russian industry’s crown jewels, Norilsk has a market value of more than $30 billion, and Potanin owns 30% of the company.

The former deputy prime minister was one of the main backers of Russia’s bid to host the 2014 Sochi Winter Olympics, and he invested heavily in the development of the Olympic village. He also controls a transport and infrastructure company, a pharmaceutical firm and a ski resort operator.

Natalia says she’s owed half of her ex-husband’s business empire, because under Russian law wealth acquired during marriage should be divided equally.

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