U.S. authorities said on Thursday they would soon bring to a close the tax fraud case against UBS , which had threatened to bring the Swiss banking giant to its knees.

The U.S. government agreed last August to drop tax-evasion charges against UBS after Switzerland promised it would transfer the details of around 4,450 clients UBS helped to dodge taxes, lifting the veil on Switzerland's cherished tradition of banking secrecy.

Swiss tax authorities had examined the clients' accounts by Thursday's deadline, and talks were being held with the United States over the final handover of information, the Swiss Finance Ministry said on Thursday.

Washington sought to obtain the names through a so-called John Doe summons, which describes the types of clients at the bank based on their actions, without specific names. A tax official said the government has received 2,000 accounts so far.

Based on information received to date and assurances by the Swiss Government, we anticipate being in a position to withdraw the John Doe summons this fall, Internal Revenue Service spokesman Bruce Friedland said in a statement.

The deal hung in the balance until Swiss parliament gave its support in June and ruled out a referendum on the issue, removing the last obstacle to UBS boss Oswald Gruebel's quest to revive the fortunes of the bank, which hauled him from retirement after the state had to bail it out.

UBS's wealthy clients had been leaving in droves as the threat of renewed legal action loomed if Switzerland failed to deliver on its promises within a year of the deal being struck.

Gruebel has assured investors that client cash should stop gushing from UBS by the end of 2010, solving the bank's final problem after it turned in a net profit of 2 billion Swiss francs ($1.9 billion) in the second quarter, its third quarterly profit in a row under Gruebel after a string of heavy losses in the financial crisis.

Switzerland's banks should not run into further trouble with the U.S. taxman now that the damaging dispute with UBS has been cleared up, Switzerland's top tax diplomat, Michael Ambuehl, said earlier this month.

(Reporting by Jason Rhodes and Kim Dixon; Editing by Will Waterman and Matthew Lewis)