Unless the Volcker rule is implemented in its "purest form" – effectively banning speculative trading by insured commercial banks – there is a chance of financial derivatives magnifying a crisis even as the crisis of 2008 gradually fades from public memory, according to Vembar Ranganathan, a financial risk consultant and former vice-president of Citicorp's swap group.

Writing in the latest issue of Central Banking journal, Ranganathan warns that despite significant progress in reforming the