Credit Suisse is reportedly hoping to prove that any hidden accounts were a lapse in control.

Credit Suisse made no comment when asked by WealthBriefing about media reports that it has frozen dozens of accounts as it tries to determine if its clients are hiding money from the US Internal Revenue Service.

The Zurich-headquartered firm pledged to come clean about secret assets amid the US Department of Justice's collaborative crackdown with the IRS on secret Swiss bank accounts.

The bank is reportedly looking at indicators such as phone numbers or powers of attorney to establish whether US citizens are the true owners of accounts not disclosed to the IRS, a person close to the matter told Bloomberg earlier this week. Any client activity on these accounts requires approval by a group within Credit Suisse, according to the source, who was not authorised to speak publicly about the matter.

When contacted by this publication, Dominique Gerster, a spokesperson for Credit Suisse in New York, declined to comment.

The bank's move to freeze accounts occurred in the past week as the US Department of Justice ramped up its investigation into why Credit Suisse failed to notify authorities of $200 million in assets held by an American client who last month pleaded guilty to conspiring to defraud the IRS, according to multiple Bloomberg sources. Credit Suisse is hoping to prove that any hidden accounts were a “lapse in control” as opposed to a criminal act, another person close to the matter told the news service.

The reports may be unsurprising to some as probes such as this one have been conducted by US authorities for some years now.

In 2009, UBS agreed with the US authorities to pay a settlement to draw a line under criminal and civil charges around its provision of offshore accounts to US citizens. The saga fired the starting gun for a number of aggressive moves by the US against Swiss banks, with several promising to stop offering offshore accounts. 

In 2013, Switzerland and the US signed an agreement under which Swiss financial institutions would state whether they had or had not run the risk of breaking rules about such accounts. Dozens of Swiss institutions reached non-prosecutions agreements with US authorities.

The Department of Justice declined to comment on the matter when contacted by this publication.