Banks can become illiquid when wholesale funding markets to not function for extended periods of time. Illiquidity quickly transforms into insolvency if liquid assets or cash flows cannot cover banks’ maturing liabilities. Since the 2008–9 global financial crisis, a new financial stability consensus has emerged whereby central banks began implementing unconventional liquidity tools. This chapter comparatively analyzes Hong Kong’s sectoral supervision with the integrated, functional, and Twin Peaks models when implementing unconventional liquidity tools. The macro- and micro-prudential characteristics of unconventional liquidity tools necessitate systemic supervision by central banks and banking supervisors. Effective systemic supervision of unconventional liquidity tools cannot be presumed merely by the presence of a systemic supervisory agency. Underlap can weaken systemic risk objectives and mandates when implementing unconventional liquidity tools because supervisory roles can become uncertain. In this context, Hong Kong’s composite systemic supervisor, the Financial Stability Committee, may not be able to properly coordinate member financial supervisors. Uncertainty can lead to tensions between Financial Stability Committee members, impeding systemic supervisory effectiveness. Tensions coupled with uncertainty can produce macro-prudential and systemic supervisory flaws when managing funding and market liquidity, heightening banking system instability.