We analyze retail central bank digital currency (CBDC) in a two-tier monetary system with bank deposit market power and externalities from liquidity transformation. Resource costs of liquidity provision determine the optimal monetary architecture and modified Friedman (1969) rules the optimal monetary policy. Optimal interest rates on reserves and CBDC differ. A calibration for the U.S. suggests a weak case for CBDC in the baseline but a much clearer case when too-big-to-fail banks, tax distortions or instrument restrictions are present. Depending on central bank choices CBDC raises U.S. bank funding costs by up to 1.5 percent of GDP.
We analyze policy in a two-tiered monetary system. Noncompetitive banks issue deposits while the central bank issues reserves and a retail CBDC. Monies differ with respect to operating costs and liquidity. We map the framework into a baseline business cycle model with “pseudo wedges” and derive optimal policy rules: Spreads satisfy modified Friedman rules and deposits must be taxed or subsidized. We generalize the Brunnermeier and Niepelt (2019) result on the macro irrelevance of CBDC but show that a deposit based payment system requires higher taxes. The model implies annual implicit subsidies to U.S. banks of up to 0.8 percent of GDP during the period 1999-2017.
This paper reviews theoretical results on financial policy. We use basic accounting identities to illustrate relations between gross assets and liabilities, net debt positions and the appropriation of (primary) budget surplus funds. We then discuss Ramsey policies, answering the question how a committed government may use financial instruments to pursue its objectives. Finally, we discuss additional roles for financial policy that arise as a consequence of political frictions, in particular lack of commitment.