Money is both the medium for transaction and the most liquid asset for banks. We examine both roles of money in an integrated framework, where banks are subject to aggregate illiquidity risk. An active central bank can replicate the constrained efficient allocation, which, however, cannot be implemented in the market equilibrium: due to moral hazard problems, banks invest excessively in illiquid assets, forcing the central bank to provide liquidity at low interest rates. An interest rate policy aiming to reduce systemic liquidity risk is dynamically inconsistent. Instead, the constrained efficiency can be achieved by imposing ex ante liquidity coverage requirement.

中文翻译：

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银行业均衡中的货币1

货币既是交易的媒介，也是银行最具流动性的资产。我们在一个综合框架中研究了货币的两种角色，其中银行面临总体的非流动性风险。积极的中央银行可以复制受约束的有效配置，但不能在市场均衡中实施：由于道德风险问题，银行过度投资于非流动性资产，迫使中央银行以低利率提供流动性。旨在降低系统性流动性风险的利率政策是动态不一致的。相反，可以通过施加事前流动性覆盖要求来实现受限的效率。