U.S. tax officials said Thursday they expect to be able to withdraw legal action against UBS AG after Swiss officials hand over the remainder of 4,450 sets of confidential client data on wealthy Americans with hidden offshore accounts at the Swiss bank, or roughly another 2,000 sets of data.

"We continue to work with the Swiss government as we move toward receipt of all account information under the agreement," the Internal Revenue Service said in an e-mailed statement marking the deadline for an agreement between the U.S. and Switzerland to be fulfilled.

Last August, Switzerland agreed that UBS would hand over 4,450 sets of client data as part of a settlement of a civil suit alleging the Swiss bank helped wealthy Americans dodge taxes in the U.S. through hidden offshore accounts.

Earlier in the day, Switzerland said it had worked through all of the 4,450 sets of data, handed over roughly half to the U.S. and was talking to officials there about how to conclude the agreement. Switzerland said the remainder of the data — believed to be most of the 4,450 cases — will be handed over by this fall.

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