Monetary Policy with Reserves and CBDC: Optimality, Equivalence, and Politics
This paper analyzes 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. It maps the framework into a baseline business cycle model with "pseudo wedges" and derives optimal policy rules: Spreads satisfy modified Friedman rules and deposits must be taxed or subsidized. It generalizes the Brunnermeier and Niepelt (2019) result on the macro irrelevance of CBDC but shows 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.