The entire industry would be benefited by swift action and system of reporting under a common umbrella, for which set standards specifying the action to be initiated at such times is clearly indicated.
Though compliance to CERT (i.e Computer Emergency Response Team) requirements would address this issue to some extent, it would be preferable to have a dedicated institutional set-up for the financial sector to report security breaches, quick responding team for major breaches, monitoring compliance and reporting to the regulators. I believe that IDRBT can play a nodal role towards building such a set up.