Central bank independence is a multifaceted institutional design. The financial component has been seldom analysed. This paper intends to set a comprehensive conceptual background for central bank financial independence. Quite often central banks are modelled as robot-like maximizers of some goal. This perspective neglects the fact that central bank functions are inevitably deployed on its balance sheet and have effects on its income statement. A financially independent central bank exhibits the adequate balance sheet structure and earnings generation capacity to efficiently perform its functions. From a long-term perspective, as far as the demand for banknotes is maintained seignorage waters down any central bank financial independence concern. However, from a short-term perspective central bank financial vulnerability may condition its effective independence. Vulnerability may be real or accounting based. However, no matter its origin, institutional solutions are needed to minimize their impact. Adequate capitalization turns out to be a key issue. Alternatively, contingent capital in the form of institutional arrangements to bear central bank losses may be a (second-best) solution. The paper analyses in the context of simple VAR model the interplay between capitalization, accounting rules and dividend distribution. This analysis is preceded by a thorough discussion of the risk-return profile of central banks net return on assets. Three main conclusions shape the input to the capitalization model. Central banks return on assets can be very volatile from a short term perspective. From a medium term perspective, natural earnings generation cycles dampen down volatility. On average, central banks net return on assets typically exhibits a discount over government debt financing cost. These observations shape the central bank financing planning problem as follows. Namely, the size of the discount relative to the social costs that would arise in case of a lack of central bank independence, along with central bank exposure to risks and the volatility thereof, determine the incentives of the government to maintain an excess of financial assets in the form of central bank capital. Actually, the working of smoothing mechanisms operating across time on central banks earnings leads to a distinction between short-term and medium term capital, i.e. the optimum capital solution is a band. In the same vein, the need to maintain optimal consistence between central bank financial strength and dividends distribution policy leads also to smoothing proporsals for pay-policy.