U.S. officials have set an ultimatum for Switzerland to hand over details on the number of Americans suspected of using Swiss banks to cheat on their taxes, Swiss media reported Sunday.
Failure to do so could mean charges against one or more Swiss banks, including Credit Suisse Group, according to the SonntagsZeitung and NZZ am Sonntag newspapers.
SonntagsZeitung reported it had obtained a copy of a letter sent to senior Swiss diplomat Michael Ambuehl by U.S. Deputy Attorney General James Cole on Aug. 31, demanding to know how many Americans may have avoided paying taxes by hiding money in Swiss banks.
The newspaper cited unnamed Swiss officials familiar with the case as saying Washington wants details on the number of Americans who had accounts containing more than $50,000 with Credit Suisse, Julius Baer, Bank Wegelin, Zuercher Kantonalbank and Basler Kantonalbank between 2002 and 2010.
The U.S. Embassy in Bern referred queries to a Justice Department spokesman, who couldn't immediately be reached Sunday.
Mario Tuor, a spokesman for the Swiss Finance Ministry, declined to comment on the letter.
Zurich weekly NZZ am Sonntag described the U.S. ultimatum as a "massive escalation" in the simmering dispute between Washington and Bern over tax evasion.
Two years ago, Swiss bank UBS AG was forced to hand over the names of thousands of American account holders and pay a $780 million fine, in a landmark case that rattled Switzerland's storied tradition of banking secrecy. The Swiss government has since signed agreements with several countries including Germany and Britain to provide greater assistance to foreign tax authorities seeking information on their citizens' accounts in the Alpine nation.
Swiss lawmakers are due to approve a revised tax agreement with the U.S. this fall.