Two weeks previous to this Bank Wegelin Request, the private bank Julius Baer was also notified that it was subject of a similar request by Washington.
U.S. authorities have more than a dozen banks under formal investigation, including Credit Suisse, Julius Baer, the Swiss Branch of HSBC, Pictet and local government-backed Zuercher Kantonalbank and Basler Kantonalbank.
123 to 63 against debating a draft law which is aimed to protect the country's banks from criminal charges in the United States for helping wealthy Americans evade tax, effectively killing the law, even though the upper house had confirmed its support earlier that day.
The Swiss government has warned that the bill's failure could prompt impatient U.S. prosecutors to indict banks, though it could still use an executive order to allow them to hand over data to try to avoid criminal charges.
"Switzerland must not take the risk of a further indictment of a bank lightly," the Swiss Bankers Association said in a statement.