South Korea’s Supreme Court has struck down a lower court’s order for billionaire Chey Tae-won to pay his ex-wife a 1.38tn won ($1bn; £788m) settlement, in a case dubbed by local media as the “divorce of the century”.

Citing a miscalculation that increased the value of the couple’s assets, it has ordered the case to be reviewed.

The case has gripped South Korea as Mr Chey heads the powerful SK Group conglomerate while his ex-wife Roh So-young is the daughter of a former president.

The marriage unravelled in 2015 after Mr Chey admitted to fathering a child with his lover.

The 1.38 trillion won payout was decided by a court in the capital Seoul in 2024. It was considered the largest divorce settlement in South Korea’s history at the time.

The court said a 30bn won slush fund by Ms Roh’s father, former president Roh Tae-woo, had helped contribute to the growth of SK Group and could be considered as her contribution to the couple’s joint assets.

Mr Chey then appealed the settlement.

On Thursday the Supreme Court ruled that the slush fund “appeared to have originated from bribes illegally received” by the former president and thus could not be considered part of the couple’s assets.

“I think it is very significant that the Supreme Court clearly declared that it was wrong to recognise that as a contribution to the couple’s joint property,” said Mr Chey’s lawyer, Lee Jae-geun.

However, the Supreme Court upheld a 2bn won alimony payment for Ms Roh.

Shares of SK fell 5.4% after the ruling on Thursday, as it was seen to prolong Mr Chey’s legal battle with his ex-wife.

But in the short term analysts believe a shake-up at SK Group is unlikely, as Mr Chey is not immediately compelled to raise funds for his divorce settlement.

He controls key subsidiaries of the group such as SK Telecom, SK Square and SK Innovation.

SK’s businesses span the telecommunications, energy, pharmaceuticals and semiconductor sectors.