Harold Hamm divorce: Oil tycoon's ex-wife rejects $1bn handwritten cheque because settlement figure is 'not enough'

Sue Ann Arnall's lawyers contest the Hamm fortune is worth $18bn – and represents a joint husband-and-wife effort

Sue Ann Arnall stands in the courthouse hall before divorce proceedings with Harold Hamm, founder and CEO of Continental Resources (Reuters) (Reuters)

One of the largest divorce cases in US history has served up another extraordinary twist after oil tycoon Harold Hamm’s ex-wife rejected a hand-written cheque for almost $1 billion.

The offer was available to cash immediately and in full, after Hamm moved enough money into a single account to cover the one-off $974,790,317.77 (£644 million) payment.

The figure – so large it barely fits on the cheque – was determined by an Oklahoma County judge in a divorce ruling in November.

But Hamm’s ex-wife, Sue Ann Arnall, has turned it down on the grounds that accepting it could hurt her chances of appealing for more, her lawyers said.

A divorce settlement cheque from Harold Hamm to ex-wife Sue Ann Arnall for the amount of 4.8m (Reuters)

Both parties are bringing appeal proceedings against the $1 billion figure, which Hamm’s lawyer Michael Burrage said was too large.

Hamm is the chief executive of drilling company Continental Resources, but says that he has lost billions in the value of his 68 per cent stake in the company after the recent fall in US oil prices.

Arnall, herself a lawyer and former Continental executive who was married to Hamm for 26 years, contends that his fortune is still worth around $18 billion (£11.8 billion) – and that the largest American oil owner was built up over those two-and-a-half decades in a joint effort.

Harold Hamm, founder and CEO of Continental Resources, enters the courthouse for divorce proceedings (Reuters)

Both parties appeared in court in Oklahoma on Tuesday, in part to clarify how much of the $1 billion should be made available to Arnall while appeals continue. Hamm has already paid out more than $20 million during the proceedings, a 10-week divorce hearing that ended in October.

Michael Burrage, Hamm's lawyer, said Arnall could still cash the cheque if she wants to, and that Hamm had borrowed funds to ensure there would be enough cash in his account to cover it.

Ron Barber, Arnall’s lawyer, said: “We are seeking clarification of the court's 10 November order at today's hearing and cannot accept any payments, pending such clarification, without jeopardising Ms Arnall's rights on appeal.”

Additional reporting by Reuters