WASHINGTON — UBS will reveal the identities of about 4,450 of its American clients who are suspected of evading U.S. taxes through secret Swiss accounts, according to details of a settlement released Wednesday.
The Swiss banking giant will turn over the client data as part of an eagerly awaited deal to resolve an Internal Revenue Service probe that sought the names of thousands of American clients of UBS — an unprecedented enforcement effort against a foreign bank.
Under the terms of the deal, U.S. tax authorities will file a treaty request with the Swiss government to obtain the UBS client data. The bank will then hand over the account information to Swiss tax authorities, who will process it for release to the United States.
“This is a huge step forward for the United States in our efforts to combat offshore tax evasion,” IRS Commissioner Doug Shulman said on a conference call with reporters.
UBS will not pay a fine as part of the agreement.
The bank and the governments of the U.S. and Switzerland agreed on a final settlement last week, but the details weren’t made public until Wednesday morning.
The criteria used to select the 4,450 UBS accounts for release are being kept confidential for 90 days as part of an IRS attempt to nudge more UBS clients into voluntarily coming clean with their taxes.
Shulman said the agency would be receiving information on various UBS account types with a wide range of dollar values.



