"The idea of banning so-called proprietary trading — conceived by former Federal Reserve chairman Paul Volcker — was a centrepiece of former president Barack Obama's efforts to build a bulwark against future crises requiring public bailouts. But the prohibition's final form, which stretched to 964 pages of regulation, has been criticised by banks as muddled and overly complex. They blame it for inhibiting market making activity that was meant to be permitted."