In 2009 UBS, the world's largest wealth manager by assets, was fined $780 million and agreed to hand over the names of U.S. clients with secret Swiss bank accounts to avoid facing criminal charges. The deal with the United States marked an historic break with Switzerland's tradition of bank secrecy.
Reuss Private Group, a Swiss wealth manager where Weil is chief executive, said on Monday the banker had been arrested while on a private visit to Italy.
"He has been detained on the basis of an international arrest warrat issued by the U.S. judiciary in 2008 in connection with allegations of aiding and abetting tax evasion during the time Raoul Weil was with UBS, which he left in 2009. Raoul Weil disputes these allegations,'' Reuss said.
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Police sources told Reuters that Weil, 53, was arrested at the 'I Portici' hotel in central Bologna and taken to the city's Dozza prison.
Reuters was not immediately able to contact Weil or his Italian lawyers. His legal representative in the U.S. did not immediately respond to requests for comment.
When Weil was indicted in 2008, his U.S. attorney said he was innocent and called the indictment against him ``totally unjustified.''
Under Italian law, the Bologna Court of Appeal will set a hearing to identify Weil. After that, Italy will have to decide whether or not to hand the Swiss banker over to U.S. authorities.
Italy has in the past cooperated with the U.S. with the exception of crimes that would be punished with the death penalty, which is banned in Italy. Under U.S. law, a conviction for tax evasion may result in fines and imprisonment.
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A UBS spokesman said Weil, who became the head of the its global wealth management business in 2007 and also sat on the bank's board, was discharged from his duties when he was indicted.
He joined Reuss Private Group in 2010 as a consultant and became chief executive at the beginning of this year.