By the skin of its teeth, BNP Paribas has absorbed its massive $9 billion settlement with US authorities, put aside money for a flat dividend this year and still kept its core Tier One capital ratio at exactly the 10% it targets as a minimum.

This fine balancing act has left little margin for error. The bank's capacity to soak up any penalties has been wiped out at a time when it faces more probes and litigation, not least of which is the foreign-exchange investigation common to multiple banks.