According to Swiss newspaper reports, U.S. authorities are seeking records of American UBS clients visited by Swiss bankers from 2001-2007.
The US is seeking around 52,000 US offshore account holders suspected of tax evasion, and an estimated 10,000 may be implicated in the latest probe.
UBS has already acknowledged that it broke U.S. law by setting up offshore banking operations in the US. As a result, the release of this information would not infringe upon bank secrecy laws, since meetings were held with clients on US soil.
The bank has already agreed the handover of 250 client records, seen as a massive blow to Swiss bank secrecy. It is thought that these 10,000 new leads may be the middle ground for compromise rather than handing over all 52,000. It is not certain how many of the 10,000 actually committed a crime.
While the US authorities can go around Swiss bank secrecy laws where international banks have carried out operations on US soil, private banking operations carried out solely within Switzerland still benefit from full banking secrecy.