The Swiss bank plea follows a years-long investigation by US law enforcement authorities that also produced indictments of eight Credit Suisse executives since 2011; two of them have pleaded guilty so far.
"Credit Suisse conspired to help US citizens hide assets in offshore accounts in order to evade paying taxes. When a bank engages in misconduct this brazen, it should expect that the Justice Department will pursue criminal prosecution to the fullest extent possible, as has happened here," US Attorney General Eric Holder said.
"This is the largest bank to plead guilty in 20 years. The bank will pay a total of USD 1.8 billion in the form of a fine of over USD 1.13 billion and nearly USD 670 million in restitution to the IRS.
"They have admitted criminal wrongdoing in a detailed Statement of Facts filed alongside the information in this case," he said.
As part of the plea agreement, Credit Suisse acknowledged that for decades prior to and through 2009, it operated an illegal cross-border banking business that knowingly and willfully aided and assisted thousands of US clients in opening and maintaining undeclared accounts and concealing their offshore assets and income from the IRS.
"Credit Suisse's guilty plea is just the latest effort by the department to slam the door shut on undeclared bank accounts, phony trusts and other foreign schemes used by US taxpayers to evade taxes," said Deputy Attorney General Cole.
"We will continue to hold to account the bankers, the brokers and other professionals in Switzerland and around the world as well as the institutions that trained and directed them to use bank secrecy laws to protect US tax cheats," he said.
In recent years, the US Department of Justice has taken public actions in India, Israel, Luxembourg, the Cayman Islands and several other Caribbean countries against American tax evaders.
"We are engaged in law enforcement actions around the world that are not yet public," he said.
Credit Suisse employed a variety of means to assist US clients in concealing their undeclared accounts, including by assisting them in using sham entities to hide undeclared accounts; failing to maintain in the US records related to the accounts; destroying account records sent to the US for client review; and using bank's managers and employees as unregistered investment advisers on undeclared accounts, according to the statement of facts filed with the plea agreement.
It also facilitated withdrawals of funds from the undeclared accounts by either providing hand-delivered cash in the US or using Credit Suisse's correspondent bank accounts in America; structuring transfers of funds to evade currency transaction reporting requirements; and providing offshore credit and debit cards to repatriate funds in the undeclared accounts.
"The bank went to elaborate lengths to shield itself, its employees, and the tax cheats it served from accountability for their criminal actions.
"They subverted disclosure requirements, destroyed bank records, and concealed transactions involving undeclared accounts by limiting withdrawal amounts and using offshore credit and debit cards to repatriate funds," Holder said.
"They failed to take even the most basic steps to ensure compliance with tax laws.
And when the bank finally began to feel pressure to correct illegal practices and comply with the law as a result of the Justice Department's investigation, of which they were notified in 2010 Credit Suisse failed to retain key documents, allowed evidence to be lost or destroyed, and conducted a shamefully inadequate internal inquiry," he said.