The humbling of two global banks in recent weeks has been greeted very differently on opposite sides of the Atlantic. Still, from the perspective of either side, large fines for interest rate rigging by Swiss bank UBS, and money-laundering by HSBC, point to the same conclusion: from now on, banks must protect their reputations as their most valuable asset.

On the US side, there has been considerable grumbling about the “lenient” treatment meted out to HSBC and UBS . Associations with Mexican drug cartels and Iranian militants or documented solicitation of price fixing usually attract the attention of federal prosecutors. Yet, while UBS’s Japanese subsidiary did plead guilty to one criminal count and two of its employees face charges, not a single HSBC employee faces any form of criminal or civil sanction. Nor has the parent entity been charged in either case. Given similar recent problems at Barclays and Standard Chartered the question from the US perspective becomes: Why are British and European banks not more law compliant?

From the British side concern is growing about the “punitive” nature of American enforcement. Why is the US “obsessed” with criminal prosecutions? In the US the idea that “too big to fail” means “too big to prosecute” has become politically unacceptable. But in the UK there remains a fear that criminal prosecutions could lead to a major bank failure, potentially destabilising international banking and chilling economic recovery.