UBS: Athens is investigating possible tax fraud

The Greek government confirmed the raid, which took place in Athens in the house of a former UBS banker in the early days of the month, news already anticipated by the Financial Times. The investigation is relating to an alleged tax evasion.

UBS bank spokesman said the institute would not have been informed by the Greek authorities in the investigation and therefore can not provide more details on the matter.

"Greece will devote its resources and enlist the assistance and expertise of cooperating countries to ferret out wrongdoing by financial institutions and their high profile clients who attempt to evade their tax responsibilities," Greek government spokeswoman Olga Gerovasili said in a statement on Tuesday.

The Greek research is based on information provided by the German state of North Rhine Westphalia. Since 2010, the German federal state in question has bought several times data of customers of banks that would help them defraud the IRS. A good number of these customers could have hidden their assets in Switzerland.