It is the surprise factor - the shock evinced by Mr Dimon - that will reignite the debate about whether regulators need to take more decisive action to curb the complexity of investment banks, to better prevent this kind of accident.
With inflation already likely to have peaked and with the ECB predicting a return to beneath the 2% target ceiling the policy adjustment process is becoming less of a factor, while one good shock is all it might take to unsaddle already fragile European confidence that could derail the euro once more.