More than 100 Swiss banks have applied to the amnesty programme of the US Department of Justice, which gives immunity from prosecution to those institutions that have helped American citizens evade taxes.

During the weekend, Kathryn Keneally, assistant attorney general for the department’s tax division, said 106 Swiss banks – one third of all the banks that received the offer – intended to sign non-prosecution agreements with the US authorities. They have filed a letter of intent before the deadline of 31 December.

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Some institutions couldn’t apply to the programme because they were already under investigation, such as HSBC Holdings and Credit Suisse. The latter, which is Switzerland’s second biggest bank, is currently negotiating its own settlement. Others have already signed non-prosecution agreements, such as UBS, the country’s largest bank, which was fined $780 million in 2009.

Banks that are granted non-prosecution agreements have to pay a fine – between 20 and 50 per cent of the value of their American clients’ undeclared assets depending on when the account was opened – as well as provide information about their clients and how the bank helped them evade taxes.

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Should you be worried if you’re an American taxpayer? No, unless you have held money on Swiss bank accounts after August 2008 and haven’t declared it yet.

In that case, you should consider applying to the Offshore Voluntary Disclosure Program, which is a personal agreement with the US authorities establishing penalties in exchange for full foreign assets disclosure. If you don’t and your bank ends up signing the non-prosecution agreement, giving up your name, you would no longer be able to apply to OVDP and you can be sure the Department of Justice won’t go easy on you.