The ex-wife of an Oklahoma oil tycoon who was awarded cash and assets worth more than $1 billion in the couple's divorce, plans to appeal the judgment on grounds that it grossly undervalued the marital wealth she is entitled to.

Sue Ann Hamm claims she was short-changed by this week's ruling even though it was one of the biggest divorce payouts in history.

Continental Resources CEO Harold Hamm was allowed by an Oklahoma County judge to keep nearly all of an estimated $18 billion rise in his company shares that occurred during their 26-year marriage.

Harold Hamm was ordered by an Oklahoma County judge to hand over close to $1 billion to his ex-wife Sue Ann Hamm this week, but she has revealed that she plans to contest the decision and believes she was entitled to more

‘Sue Ann is disappointed in the outcome of this case. She dedicated 25 years as Harold’s faithful partner in family and business,’ said Ron Barber, one of the attorneys on her legal team, told Reuters on Thursday.

Special Judge Howard Haralson found that Hamm, 68, should pay Mrs Hamm a total of $995.5 million, with about a third of the funds, or $322.7 million, to be paid by the end of the year, the filing revealed.

Hamm will then be required to pay the rest of the judgment, some $650 million, in installments worth at least $7 million per month.

She was also awarded additional assets, including a California ranch and an Oklahoma home, worth tens of millions more.

Sue Ann Hamm has already been awarded around $25 million since the case was filed in 2012.

To secure the judgment, Judge Haralson has placed a lien on 20 million shares of Continental stock.

The ruling, which is subject to appeal, comes after a ten-week divorce trial which ended last month.

Forbes named the oil tycoon the 30th richest person in the U.S. in 2012 and 76th richest person in the world. His fortune is estimated at $14billion today

Hamm started Continental in 1967, and about 68 per cent of the firm's shares are in his name.

His stake was worth more than $18 billion when the trial started in August. It's worth around $13.5 billion today.

Since the couple wed in 1988, Continental has grown from a small-time driller worth less than $50 million into a $20 billion behemoth and one of Oklahoma's largest companies.

Because Harold owned his shares before he and Sue Ann were married, they belong to him.

But under Oklahoma law, their 'active' appreciation since 1988 is subject to 'equitable distribution' with Sue Ann, a former executive at Continental who filed for divorce from Harold in 2012.

Her legal team contends that the amount of marital wealth the court should divide is more than $17 billion, a sum that included most of Harold's stake in Continental a few months before the trial began.

The Hamms own four houses together including this vast property in an exclusive enclave of Nichols Hills, Oklahoma

High-life: Sue Ann Hamm and the couple's daughter Jane are pictured at a lunch for the Wall Street Journal Innovator of Year award

In a court filing from 2013, Mrs Hamm alleged that her husband was having an affair, which prompted her to file for divorce.

Mrs Hamm, 56, has held key posts at Continental, but she no longer works for the company.

Court filings showed that his attorneys argued that the couple's shared wealth is a tiny fraction of that amount. The couple never signed a prenuptial agreement.

Harold Hamm's leadership at Continental is central to the case.

In court, his lawyers attributed most of Continental's success not to Hamm's business savvy but to factors beyond his control - that market factors such as rising oil prices, or decisions made prior to marriage caused Continental's growth. The trial ended on October 9.

In Oklahoma, a divorce appeal can be heard by a State Court of Appeals panel or the Oklahoma Supreme Court.

A higher court could review the case and affirm Haralson’s judgment, or modify the award. It could also send the case back to Haralson to be re-tried.

Family law experts say the process could take anywhere from 18 months to several years.

Video Source: YouTube

Harold Hamm pictured with Mitt Romney during his run for the White House. The oil tycoon donated close to $1million to the Republican candidate's campaign

This is the second divorce for Hamm after he divorced his first wife, Judith Ann, in 1987. They have three children together.

In 1988, Hamm married Sue Ann, an economist and lawyer. The couple had two daughters, Jane and Hillary.

The oil magnate lives in Oklahoma City and owns homes in Enid, Oklahoma and Nichols Hills, Oklahoma.

The vast Nichols Hills property is believed to be worth in the region of $3million.

Forbes named him the 30th richest person in the U.S. in 2012 and 76th richest person in the world.

He had humble beginnings, growing up in rural Oklahoma where he was the 13th child of Oklahoma cotton sharecroppers.

Hamm, pictured at his boyhood home in Lexington, Oklahoma, had humble beginnings as the 13th child of cotton sharecroppers

Mr Hamm spent his youth picking cotton, before starting his career at 20 by scrubbing the scum out of oil barrels. He worked his way up and was eventually able to drill his own wells.

Fond of eating at burger bars, Mr Hamm has a reputation for being down-to-earth and drives his own truck.

His big breakthrough came in the Nineties, when he helped discover the Bakken field of North Dakota, the largest new U.S. oil prospect since the Sixties.