Institutional shareholders or any individual shareholder in any enterprise, be it a financial institution or a non-financial enterprise, are expected to be the first and foremost watchdog of its operations. The watchdogs are supposed to look after the best interests of the enterprise rather using their authority to advance their own agendas.
As is generally observed the sinews of good behaviour can hardly be reinforced by regulation. Financial regulations are not designed to catch deceit but to create markets and promote good corporate habits - habits that are indeed transparent to savers and investors who can vote with their money and why not with their feet, if the need arises.