In June, British bank Barclays Plc was fined $453 million for manipulating Libor benchmark interest rates, becoming the first bank to settle in the ongoing probe, prompting the resignation of its chairman and chief executive.

UBS was the first bank globally to report suspected rate rigging, and has said it has received conditional immunity from some authorities for cooperating in their probes.

A UBS spokeswoman told Reuters that the bank was in the midst of discussions with authorities in the United States and Britain in connection with Libor investigations and has been cooperating fully with the regulatory and enforcement authorities, but gave no further details.

Christopher Hamilton, spokesman for Britain's Financial Services Authority, declined to comment beyond confirming the already established fact that the FSA is investigating UBS.

The Commodity Futures Trading Commission and the U.S. Justice Department, investigating the Libor matter in the United States, could not immediately be reached for comment.

Other banks are also anxious to draw a line under the probe, which is well into its second year. British bank RBS said last month it hopes to reach a settlement on its part in the rate-rigging scandal - likely to result in fines for the bank - and expects to start talks soon.

Morgan Stanley estimated that 11 global banks linked to the Libor scandal could face $14 billion in regulatory and legal settlement costs through 2014.

The reliability of the London interbank offered rate, or Libor, has been cast into doubt by the rate manipulation accusations. Libor is intended to measure the rate at which banks lend to one another and is used as a benchmark for $300 trillion of contracts and loans across the world.

Switzerland is also investigating 12 U.S., European and Japanese banks suspected of conspiring to manipulate interbank lending rates. They include Credit Suisse, Deutsche Bank, HSBC Holdings and RBS.

"In Switzerland we are still investigating the case. We are in contact with other authorities," said Competition Commission official Olivier Schaller, but provided no further details.

FINMA spokesman Tobias Lux said the Swiss regulator was making ongoing efforts to clarify the issue, but declined to comment further.

(Additional reporting by Sakthi Prasad in Bangalore; Editing by Edmund Klamann and Mike Nesbit)

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