摘要：In this paper we set out a three-pillar monetary-financial framework to (i) analyze, categorize and compare past, current and emerging means of payment; to (ii) capture their creation and destruction processes through sectoral balance sheet dynamics; and to (iii) identify the inherent risks to the current monetary-financial system, also known as the fractional reserve banking system. These risks, which stem from sudden shifts in money demand and supply, are as follows: (I) risk of a cashless society; (II) risk of structural bank disintermediation; (III) risk of systemic bank runs; (IV) risk of currency substitution; and (V) risk of economic and financial bubbles. This framework will guide the assessment of the central bank digital currencies (CBDC), which are considered as the next step in monetary evolution. We will analyze two large groups of CBDC proposals: (i) proposals aimed at complementing cash and bank deposits; and (ii) proposals aimed at replacing all bank deposits with CBDCs. We find that once CBDCs are issued in both sets of proposals, there is always a trade-off between low levels of (I), (IV), (V), risks and high levels of (II) risk. This trade-off could also be defined as the CBDC dilemma, which states that in most CBDC proposals it is impossible to have both of the following at the same time: (1) low levels of (I), (IV) and (V) risks; and (2) low levels of (II) risk. Finally, we suggest that further research on CBDCs should focus on the second group of proposals on a phase-in basis in order to also mitigate the structural bank disintermediation risk and hence to overcome the CBDC dilemma.
