* Barrage of criticism over UBS handling of tax probe

* Shares have lost more than a quarter in 2009

* Analyst expects increased volatility in bank shares (Adds more details, comment)

By Rupert Pretterklieber

ZURICH, Feb 23 (Reuters) - Shares in Swiss banking giant UBS (UBSN.VX: Quote, Profile, Research)(UBS.N: Quote, Profile, Research) fell to a new all-time low on Monday, dropping below 10 Swiss francs after a barrage of criticism over the lender's handling of a U.S. probe into tax fraud.

UBS, the world's largest banker to the rich, agreed last week to pay a $780 million fine and disclose the identity of about 300 of its U.S. clients to avert criminal charges it was facing under the U.S. investigation. [ID:nTHO251627]

"As a consequence of the ongoing 'political turmoils' and power demonstrations of some countries' political leaders, we expect increased volatility for Swiss banks' shares until more clarity arrives," said Rainer Skierka, analyst at asset manager Sarasin.

The UBS settlement was backed by the Swiss government, but experts said it opened cracks in Switzerland's famous bank secrecy laws, and UBS is still facing a civil case in which U.S. authorities are seeking access to the names of another 52,000 clients.

A host of countries have already expressed their concern over losing tax revenue because of havens such as Switzerland, which alone manages nearly one third of an estimated $7 trillion of global offshore wealth.