A third of Swiss banks offered amnesty from criminal prosecution by the US over helping – or possibly helping – US citizens evade tax have chosen to join the Department of Justice programme so far.

A third of Swiss banks offered amnesty from criminal prosecution by the US over helping – or possibly helping – US citizens evade tax have chosen to join the Department of Justice programme so far, Bloomberg reported, citing various sources.

A US federal prosecutor is reported to have said that the number of banks signing up to the programme, signed with the Swiss government last August, has exceeded expectations.

A number of Swiss banks, such as Vontobel, Lomard Odier and Banque Cantonale Vaudoise, have signed the programme. There are a number of different categories that firms can state they fall into, depending on whether they think they have violated laws about helping US tax evaders, or not.

The US government gave more than 300 Swiss banks a deadline of until 31 December last year to seek non-prosecution agreements if they have “reason to believe” they violated tax laws. Some 106 sought to join the initiative, which requires participants to disclose how they helped US citizens conceal assets, hand over data on undeclared accounts and pay penalties.

The news service said that Kathryn Keneally, an assistant attorney general in the US Department of Justice tax division, cautioned the American Bar Association conference in Phoenix that the final figure may change. She didn’t name any banks seeking to take part in the programme, which is not open to 14 institutions already under criminal scrutiny, such as Credit Suisse and HSBC, the report said.

To obtain an amnesty with the US, banks must pay 20 per cent of the value of accounts not disclosed to the Internal Revenue Service on 1 August, 2008, and 30 per cent for such accounts opened between then and February 2009 and 50 per cent for accounts opened afterward.

The categories in the programme work in the following way: banks under criminal investigation are known as category 1 banks; those seeking non-prosecution agreements are category 2 banks. Category 3 banks are those who are sure they do not have a problem.