Since Arthur Andersen, a giant accountancy firm, collapsed after being found guilty of obstruction of justice in 2002, the prevailing wisdom has been that no financial firm could survive a criminal conviction. Various financial licences and permissions, after all, depend on the regulators' agreement that a firm is fit for the task; clients also make similar, if less formal, judgments. Yet on May 19th Credit Suisse, a multinational bank based in Switzerland, pleaded guilty to a criminal charge of having helped its customers elude America's tax authorities.

The plea came with an enormous fine: $2.8 billion, much more than the $780m paid in 2009 by UBS, another big Swiss bank, for much the same offence. Although Credit Suisse seems to have been quite brazen in its attempts to fox the Internal Revenue Service-sending private bankers to visit American clients using tourist visas, for example-it appears to have catered to far fewer tax-dodging customers than UBS. As has been the case in many recent legal encounters between American regulators and the banks they supervise, there was no clear formula to explain the size of the fine. Shrugging bankers refer simply to "regulatory inflation".

The potential consequences of the criminal conviction are far bigger. Clients scattered from Andersen after its conviction, precipitating the firm's collapse and the loss of thousands of jobs. Mindful of this example, banks have fiercely resisted admissions of guilt in all their dealings with America's regulators.

Prosecutors, also worried about unintended consequences, have been hesitant to insist-especially since Andersen's conviction was overturned on appeal. UBS, for instance, did not admit guilt, instead entering a deferred-prosecution agreement, whereby the Department of Justice has suspended legal action against it in exchange for a series of reforms, in addition to the fine. Indeed, in spite of the popular belief that wayward bankers precipitated the financial crisis, no bank in America has admitted to, or been convicted of, any crime related to it.

SYNOPSIS: A big financial firm pleads guilty to a criminal charge and lives to tell the tale.

QUESTION: Are some employees at Credit Suisse "bad apples" or is Credit Suisse a "bad barrel"?