When monetary policy for financial stability backfires: Communication with strategic banks
中文摘要
我们构建了一个模型，其中中央银行将金融稳定考量纳入其货币政策与沟通决策，而系统重要性银行则策略性地选择资产组合以影响政策。由于对经济冲击作出充分反应会产生威胁银行稳定的政策意外，中央银行对这些冲击反应不足，这与美联储在2023年银行业危机期间的反应一致。预见到这种迁就，银行调整其资产组合以提高加息的金融稳定成本，从而将货币政策拉向更低利率，同时也使中央银行有动机宣布高于其预期将设定的未来利率。因此，金融稳定方面的考量可能适得其反，产生一种新颖的反应性–可信度权衡：中央银行事后对银行风险敞口的迁就越多，其前瞻指引在事前的可信度就越低，这使得银行更难使其资产组合与未来政策保持一致，并使其更容易暴露于政策意外之中。即使社会重视金融稳定，任命一位对金融稳定赋予较低权重的中央银行行长仍对社会有利。吊诡的是，当更可信的前瞻指引所带来的收益超过政策影响力损失时，就连银行也可能偏好这样一位中央银行行长。
Abstract
We develop a model in which the central bank incorporates financial stability concerns into its monetary policy and communication decisions, while systemic banks strategically choose portfolios to influence policy. Because fully responding to economic shocks would generate policy surprises that threaten bank stability, the central bank underreacts to those shocks, consistent with the Federal Reserve’s response during the 2023 banking crisis. Anticipating this accommodation, banks tilt their portfolios to increase the financial-stability costs of rate hikes, pulling monetary policy toward lower rates while giving the central bank an incentive to announce higher future rates than it expects to set. Financial stability concerns can therefore backfire, creating a novel responsiveness–credibility trade-off: the more the central bank accommodates banks’ exposures ex post, the less credible its forward guidance becomes ex ante, making it harder for banks to align their portfolios with future policy and leaving them more exposed to policy surprises. Even when society values financial stability, it benefits from appointing a central banker who places less weight on it. Paradoxically, even banks may prefer such a central banker when the benefits of more credible guidance outweigh the loss of policy influence.