A Theory of Liquidity and Regulation of Financial Intermediation
研究一个Diamond-Dybvig模型，在不可观测的流动性冲击和私下交易下，竞争均衡无效率，社会计划者通过扭曲利率改善风险分担，并提出对金融中介短期资产投资比例的限制来实现最优。
This paper studies a Diamond-Dybvig model of providing insurance against unobservable liquidity shocks in the presence of unobservable trades. We show that competitive equilibria are inefficient. A social planner finds it beneficial to introduce a wedge between the interest rate implicit in optimal allocations and the economy's marginal rate of transformation. This improves risk sharing by reducing the attractiveness of joint deviations where agents simultaneously misrepresent their type and engage in trades on private markets. We propose a simple implementation of the optimum that imposes a constraint on the portfolio share that financial intermediaries invest in short-term assets. Copyright Copyright © 2009 The Review of Economic Studies Limited.