Coutts said it will co-operate with the US Department of Justice (DOJ) in discovering whether some clients in its Swiss unit may have avoided US tax.
In a statement within its parent Royal Bank of Scotland's full year numbers, Coutts said it had 'notified the DOJ it intends to participate in the programme based on the possibility that some of its clients may not have declared their assets in compliance with US tax laws.'
The programme requires a detailed review of all US-related accounts and is due to be completed with results presented to the DOJ later in 2014.
In August 2013, the DOJ announced a programme for Swiss banks to settle the long-running dispute between the US tax authorities and Switzerland regarding the role of Swiss banks in concealing the assets of US tax payers in offshore accounts.
The programme provides Swiss banks with an opportunity to obtain resolution, through non-prosecution agreements or non-target letters, concerning their status in connection with the DOJ's investigations.
Yesterday a report by a US congressional committee claimed Credit Suisse had 'helped US tax evaders' avoid billions in tax.