Bank Capital and Financial Stability: An Economic Trade-Off or a Faustian Bargain?
本文综述了银行资本在金融稳定中的作用，指出社会最优资本水平可能高于银行私人最优水平，因此需要资本监管，但监管可能带来成本。实证表明高资本与更多贷款、更高流动性创造和更高生存概率相关，而低资本则增加系统性风险和救助概率。
Financial crises impose large and persistent social costs, making banking stability important. This article reviews the central issues surrounding the role bank capital plays in financial stability. Because the socially efficient capital level may exceed banks’ privately optimal capital levels, regulatory capital requirements become germane. But such requirements may entail various bank-level and social costs. Thus, despite agreement that higher capital would enhance banking stability, recognition of these costs has generated theoretical disagreement over whether capital requirements should be higher. Empirical evidence reveals that, in the cross section of banks, higher capital is associated with higher lending, higher liquidity creation, higher bank values, and higher probabilities of surviving crises. Moreover, increases in capital requirements are met with modest declines in lending. The overarching message from research is that lower capital in banking leads to higher systemic risk and a higher probability of a government-funded bailout that may elevate government debt and trigger a sovereign debt crisis. Thus, capital regulation reform, as well as tax policy, should seek to increase bank capital. This article discusses the contemporary thinking on these issues and concludes with open research questions.