A City tycoon hit by the recession has failed in court to cut an £11m divorce settlement with his former wife.
Brian Myerson, 50, agreed the deal from £25.8m of assets, including shares in his company, last year.
Mr Myerson told the Court of Appeal the value of the shares had dropped so much that instead of receiving £14.6m, he was half-a-million out of pocket.
But three appeal judges ruled that "natural price fluctuation" did not justify a change in the settlement.
After the ruling, the tycoon's spokesman said: "Mr Myerson is disappointed that the court failed to recognise that the economic downturn had rendered his divorce settlement unfair.
"The aim of Mr Myerson's appeal has always been to ensure that the division of assets with his ex-wife was equitable and he will now take his appeal to the House of Lords.
"A separate consequence of this appeal is that in July the High Court will hear a freestanding application to cancel the further payments that are presently due to his ex-wife under the terms of the existing settlement. That hearing will be in private."
The couple married in December 1982 and have two sons and a daughter.
Under the divorce settlement reached in Match last year, Mr Myerson's sculptor ex-wife, who lives in Hampstead, north London, will be paid a total of £9.5m over four years. She also received a £1.5m property in South Africa.
It was agreed that she should get a cash settlement and he would keep all the shares in his company, Principle Capital Investment Trust, which has offices around the world.
The court was told the value of each of the shares had fallen from £3 to 27.5 pence since the settlement.
Martin Pointer QC, representing Mr Myerson, told the judges: "The husband's case is that the unforeseeable and unforeseen combination of forces at play within the global economy has undermined the assumptions upon which the order was made."
Mr Pointer said the wife's share of the total assets under the order would be 105% and the husband's would be minus 5%.
"Arguably it could be worse than that," he added.
Giving the court's ruling, Lord Justice Thorpe said: "When a businessman takes a speculative position in compromising his wife's claims, why should the court subsequently relieve him of the consequences of his speculation by rewriting the bargain at his behest?"