Sue Ann Arnall, the second wife of Harold Hamm, received a cheque from her husband during the divorce process for an incredible $975 million (worth £644 million). It was one of the biggest divorce settlements of all time - as the couple had no pre-nup - but she decided it wasn't enough to settle the marriage, and on Tuesday her lawyers sent the cheque back.
Hamm is the billionaire Chief Executive of the Continental Resources oil company. The Daily Mirror reported that before the marriage in 1988 he already owned substantial shares in the company, but the firm was only worth $33 million. Now it is worth $13 billion, and State law says Arnall is entitled to her share of the increase.
After the divorce hearing, he was ordered to pay $974,970,317.17, and duly wrote out a cheque. This is in addition to the millions he has paid to his ex-wife for ongoing expenses as the divorce proceedings have rumbled on.
However, the Daily Mail reported that Arnall doesn't think this is enough of a payout from a man said by Forbes to be worth $5.2 billion, and estimated by her to be worth $18 billion.
Part of her argument hinges on the fact that the court will not award her any of the growth in the value of his net worth due to 'passive' factors, such as the rising oil price. She is arguing that it has not sufficiently considered active changes in the company and strategy. She also adds that as an executive of the company, the court didn't fairly value her own contribution.
In an unusual twist, Hamm is also appealing the ruling, because he thinks the court awarded her too much money. The divorce proceedings could rumble on for years.
Arnall is eventually likely to receive an impressive payout, but she will have to go some way to beat the huge sums handed over in the biggest divorce settlements in history. Many of them remain closely-guarded secrets, but some of the public numbers include:
In May last year Russian oligarch, Dmitry Rybolovlev, was ordered to pay his ex-wife Elena $4.5 billion. She had filed for divorce five years earlier.
In 1999 Jocelyn Wildenstein, received $2.5 billion in her divorce from art dealer Alec Wildenstein. She is best known for her extreme plastic surgery.
In 1999 Rupert Murdoch and his wife Anna split, and she was awarded $1.7 billion. Seventeen days later he married Wendi Deng, from whom he has since been divorced in an undisclosed settlement.
In 2008 Formula One's Bernie Ecclestone divorced his model wife Slavica, and paid a reported £1.2 billion settlement. However, court papers show that in the years since he has been paid £100 million a year from her trust fund, and it is not known how long those payments will continue.
In 1982 Saudi businessman Adnan Khashoggie, split from his English wife Soraya. She received an estimated settlement of $874 million.
In 2009 Mel Gibson and his wife Robyn split and she was awarded half his net worth at the time - $425 million. This is clearly significantly less than the others on the list - but is included as the largest celebrity divorce of all time.
Meanwhile, a notable absence from this list is Roman Abramovich, who split from his wife Irina in 2007. At the time he was said to be worth more than $18 billion, and under Russian law she could have fought for half his wealth. However, she only requested a settlement of $300 million.
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