Up to eight offshore banks are being investigated by a US federal grand jury for aiding tax evasion, according to details on the Justice Department’s website detailing its actions against such institutions.

The department disclosed the number of offshore banks under investigation when it listed its progress to date in dealing with such banks under what is known as the Tax Division's Offshore Compliance Initiative. In 2009, prosecutors charged Swiss bank UBS with aiding tax evasion by US clients. UBS paid a $780 million fine to settle criminal charges; in a separate, civil case, the US and Switzerland permitted the bank to hand over 4,450 client account names to the US. The bank, along with the likes of Wegelin and Julius Baer, no longer provides offshore banking to US clients.

“The prosecution results so far have been encouraging: To date, approximately 150 grand jury investigations of offshore banking clients have been initiated, of which 30 cases have been charged, with 24 guilty pleas having been entered, 2 convicted after trial, and 4 awaiting trial,” the DoJ said on its website.

“A number of facilitators who helped clients hide assets offshore at UBS and other banks have been indicted, resulting in ten bankers and two attorneys being charged and awaiting trial, and one advisor being charged and convicted. In addition, grand jury investigations have been opened into eight additional offshore banks across the world,” it said.

The names of the eight banks were not identified. This publication was unable to reach the DoJ for comment at the time of going to press.

Recently three large Israeli banks - Bank Hapoalim, Bank Leumi le-Israel BM and Mizrahi-Tefahot - were named by Reuters as being involved in a US tax probe, according to sources close to the matter.

Countries such as the US, Germany, France and the UK have sought to stem the outflow of tax revenues to offshore locations in the wake of the 2008 financial crisis, which saw national coffers fall heavily into the red. In their defense, international financial centers have argued that they are being unfairly pilloried for problems stemming from the major economies and that the war on offshore centers is a form of financial protectionism.

The department claimed that its enforcement efforts have “dealt fabled Swiss bank secrecy a devastating blow,” adding that it “should yield information on thousands of additional US offshore account holders who have undisclosed accounts at UBS and other banks”.

“Moreover, the publicity surrounding the Tax Division's enforcement action and the subsequent settlement has already produced dramatic behavior changes. The IRS credits these two agreements with prompting an unprecedented number of taxpayers - nearly 18,000 in the 18-month period concluding in February 2011, in contrast to the fewer than 100 typical in previous years - to 'come in from the cold' and voluntarily disclose to the IRS their previously hidden foreign accounts and also to agree to pay hundreds of millions of dollars to the US Treasury,” the DoJ continued.