Igor Olenicoff, a California property magnate, has added racketeering charges to his $500 million lawsuit against UBS and individuals who, he asserts, sold him overseas investments as tax-free accounts, according to media reports.

Mr Olenicoff agreed in December 2007 to pay federal authorities $52 million in taxes and penalties after pleading guilty to criminal tax evasion charges.

Now he has added allegations including the racketeering charge, to his original filing of September 2008.

The suit says UBS, four other companies and 25 individuals “robbed” him by charging fees or simply pocketing his money, while also exposing him to criminal charges and losing his company over $100 million in business.

Mr Olenicoff’s attorney, William King, said: “The issue isn’t his tax penalties. It’s that he thought he was doing something legal from a tax perspective and he trusted their advice and they were stealing from him.”

One of the defendants, Bradley Birkenfeld, has pleaded guilty to criminal charges related to the scheme in Florida. Last week, a judge in Florida declared another defendant, ex- UBS executive Raoul Weil, a fugitive from justice.