A Paris court found Mr Soros guilty of profiting from inside knowledge of a 1988 takeover bid for Societe Generale, a French bank.

Mr Soros, who was not in court, denied the allegations.

In a statement he said he was "astounded and dismayed" by the ruling, and would "appeal the decision to the highest level necessary".

"Let me repeat now what I have maintained from the start: at no point was I in possession of inside information regarding Societe Generale," he said.

"The charges against me are unfounded and without merit."

His lawyers had argued that the incident was too far in the past to achieve a fair trial.

Two of his co-defendants, Lebanese financier Samir Traboulsi and Jean-Charles Naouri, an aide to former finance minister Pierre Beregevoy, were acquitted.

Cashing in

The charges relate to a raid on Societe Generale by tycoon Georges Pebereau, who built up a substantial stake in the bank before trying to take control.

George Soros

Born 1930 in Budapest Graduated from the London School of Economics in 1952 Emigrated to US in 1956 His Quantum Fund has made an average 31% annual return for past three decades His Open Society Institute charity has operations in 50 countries Founded Central European University in 1992 Notorious for profiting from collapse of sterling in 1992

The bid failed, but not before the bank's share price had more than doubled.

Mr Soros and three other defendants, the court found, bought Societe Generale stock when it was cheap, and cashed in their investment when the price rose after the bid became public.

Two other businessmen implicated in the scandal - Edmond Safra and Robert Maxwell - have since died.

The affair was widely seen as a symptom of the corruption of public life in France under the presidency of Francois Mitterrand, from 1981 to 1995.

Mr Pebereau, who has never been charged with any offence in relation to the Societe Generale deal, was acting at the instigation of Mr Miterrand's socialist administration, which opposed the bank's privatisation under the previous government.

High profile

Mr Soros is no stranger to controversy.

He is widely known as the man who broke the pound, after helping force sterling out of Europe's exchange rate mechanism in 1992.

Mr Soros, Hungarian-born but domiciled in the US, was also reportedly the first American to earn a billion dollars in a single year.

In recent years, he has shifted his focus to his wide range of charitable projects, which concentrate on developing democracy and education in Eastern Europe.