JPMorgan Chase this week became the second Wall Street bank after Goldman Sachs to face a large fine and a stiff warning over its sales of mortgage-backed bonds in the last days of the housing bubble in spring 2007. Others are to come, perhaps including Merrill Lynch, Deutsche Bank and Citigroup.

It is no coincidence that the Wall Street banks have lobbied with such energy against efforts to force trading of more derivatives on to exchanges and through clearing houses. They do not want the black box of fixed income and derivatives trading, which has provided so much of their profits for so long, to be exposed to plain view.

The failure of US prosecutors to secure criminal convictions against any senior bankers or hedge fund managers apart from Raj Rajaratnam is a let-down. They have been defeated by the difficulty of proving fraudulent intent in the deceptions that flourished as banks struggled with mortgage losses.