Financial crises have a tendency to expose the financial system’s inability to absorb large systemic shocks, the critical role of liquidity channels, and financial institutions with fragile balance sheets. Pinpointing the causes of systemic risk challenges supervisors because the range of risks are virtually unlimited. This chapter argues that the definition of financial stability must be revisited to enhance the efficacy of financial supervision by drawing upon the lessons learnt from the 2008–9 global financial crisis. Defining systemic risk requires a real-time perspective of risk transmissions between the financial system components. Supervisors should appreciate financial agglomeration, the interconnectedness of the financial system, and behavioural economics when regulating systemic risk. Liquidity mismatches that destabilize financial institutions’ balance sheets and the capacity to raise funding can cause financial instability. The inability of the Hong Kong Monetary Authority to control monetary policy constrains its power to fully manage these liquidity risks. Mitigating financial instability caused by systemic liquidity risks requires an understanding of prudential regulation and the management of monetary policy to stabilize bank balance sheets. Financial architecture must be properly utilized by supervisors to restore the orderly and rational functioning of the financial system.