Credit Suisse chief executive Brady Dougan said the bank is working hard to resolve its fearsome tax investigation by US authorities, but admitted to shareholders at the annual meeting that "the outcome and timing remain uncertain".

"We certainly understand that the sooner we can get to a resolution and eliminate the uncertainty on this, the better. At this time, we are focused on achieving a manageable outcome and putting this issue behind us," Dougan told shareholders at the meeting in Zurich.

In tandem, Credit Suisse chairman Urs Rohner said the bank was "doing everything" to reach a settlement with US authorities over tax evasion schemes involving rich American account holders.

He said: "We are doing everything we can to resolve this matter within the given framework of US and Swiss law in the best possible way and in a timely manner so that we can successfully move ahead with the transformation of our bank.

"To the extent that errors were made by the bank, it has to assume responsibility," he added.

Rohner said that because the US Department of Justice (DOJ) investigations are continuing, he could not "comment on the details".

US Probe

Credit Suisse found itself placed on a prosecution hit-list of Swiss private banks and wealth managers, some of which have since been forced to close due the severity of financial sanctions imposed by US authorities.

An unrelenting assault on once-hallowed Swiss banking secrecy strictures was kicked off in 2007 at UBS, which later agreed a $780m deferred prosecution agreement with the US. Credit Suisse is reputed to have set aside as much as $1.6bn to get the Department of Justice off its back.

Swiss finance minister Eveline Widmer-Schlumpf met US Justice Minister Eric Holder in Washington last week to discuss the tax dispute. She sought fair and equal treatment of Swiss banks in the investigation.

Last month, New York's top bank regulator Benjamin Lawsky, breathing down the neck of Credit Suisse over the extent to which it facilitated tax evasion by US clients, sought documents from the bank.