The influence of central bank that has utilized all given policy options to prevent a proliferation of the 2008 financial crisis is very deep and extensive, especially related to system risk regulation which has emerged after the recent global financial crisis as a new financial reform. Even further, the central bank’s unique decision-making mode is now affecting overall discussions about restructuring current regulatory structures in the name of systemic risk regulation and macroprudential supervision. In fact, the central bank may favor a rational decision-making mode based on more sophisticated econometric and quantifiable complex modeling system and rules-based regulation over principles-based regulation which has been regarded as less predictable and more discretionary. In addition, the central bank may prefer to choose a kind of risk-based decision-making mode based on scientific rationality compared to normative rules and general principles of economic justice which are very difficult to predict its results. Thus systemic risk regulation may be able to incentivize regulators to separate conduct-regulation from prudential-regulation, and relocate the conduct-regulation and supervision to another regulatory body that is different from central bank, while merging prudential-regulation into monetary policy jurisdiction which has yet been largely checked by onerous judicial review and administrative action. However, in the event of an unforeseen financial crisis, what is the most needed for systemic risk regulators is to ensure that stakeholders are fully aware of the necessity of extraordinary emergency measures the regulators have urgently requested, rather than trying to establish more complicated risk-assessing modeling systems or excusing a lack of appropriate data to calibrate. Indeed, ‘trust’ is the most crucial to make them get what they really need to contain devastating systemic risk.