Credit Suisse may reach a settlement with US authorities worth more than $800m by the middle of 2014 over its part in helping American taxpayers evade the Internal Revenue Service by hiding their cash in Switzerland's banking system.
According to the Wall Street Journal (WSJ), citing anonymous sources, talks are in their early stages but the deal looks set to trump a $780m settlement between Swiss bank UBS and US authorities over the same tax evasion issue. It would be the biggest fine so far.
A Credit Suisse spokesman did not immediately reply to a request for comment. No comment was given to WSJ by Credit Suisse.
The US Department of Justice (DoJ) offered a deal to Swiss banks, backed by the European state's government, to disclose account details of American customers who held assets with them in order to evade tax.
In exchange for data on secret accounts and information on how they hid US taxpayers' assets, as well as a fine, the DoJ would drop any potential prosecutions of the Swiss banks.
To avoid prosecution, banks must pay the IRS 20% of the value of undeclared accounts set up before 1 August, 2008. Those set up between then and February 2009 must pay a 30% penalty, which rises to 50% for the period after that to now.
Switzerland is thought to have attracted more than $2tn (£1.3tn, €1.5tn) in offshore deposits, according to certain estimates.
The Swiss government backs the US evasion scheme. It encouraged banks to sign up and says the deal respects its legal system and sovereignty, as well as promotes cooperation between itself and the US.
On 31 December, 2013, the DoJ's amnesty deadline passed. Banks worked hurriedly with armies of lawyers and accountants to meet the deadline to sign up to the deal.
Swiss Bankers Association (SBA) spokeswoman Sindy Schmiegel said the auditing process was long and expensive, which is why it is "really a painful program".