During the financial crisis of 2008, numerous banks failed, and many received government support. 为了应对这场危机, Congress passed the Dodd–Frank Wall Street Reform and Consumer Protection Act of 2010 to strengthen the banking sector and thwart future financial crises. This policy change tightened capital and liquidity requirements in order to deter risky bank lending, 帮助银行应对未来的资金冲击, 并支持银行维持足够高的特许经营价值.1

在他们的论文中银行业动态定量模型中的资本缓冲费城联邦储备银行大阳城集团娱乐网站学家 巴勃罗·D 'Erasmo 和费城联储 访问学者院长Corbae of the University of Wisconsin–Madison and the National Bureau of Economic Research (NBER) study how much the Dodd–Frank Act has impacted bank exit rates, 贷款模式, 贷款利率水平, 以及大小银行的市场份额. 他们通过开发一个不完全竞争的模型来做到这一点, where a set of large banks that have market power interact with a wide set of competitive banks. 更一般的, they examine (i) how regulatory policies affect banking sector stability and market structure, (2)市场结构对政策有效性的反馈效应.

作者分析了大银行和小银行行为的差异. 他们证明，大银行的资本缓冲通常比小银行小. (也就是说，大银行超过监管要求的资本金较少.这主要是因为大型银行的资金来源更为多样化, 这使得它们不太容易受到资金中断的影响(也就是说, 流动性冲击). 此外, Corbae and D’Erasmo report, virtually all of the entry and exit from the U.S. 银行业已经发生在小银行中. These “fringe” banks tend to enter the sector during expansions of the gross domestic product and exit during economic downturns.

随着时间的推移，银行业变得越来越集中. U的数量.S. 银行数量从1984年的1.1万家降至2016年的不到5000家. 与此同时, the market share (as measured by assets) of the top 10 banks rose from 27 percent in 1984 to 58 percent in 2016. This translates into an approximate 50/50 asset split between the 10 largest banks and the rest of the sector. 不断上升的集中度促使作者构建了一个美国大阳城集团娱乐网站增长的模型.S. banking sector with imperfect competition, whereby some banks are dominant and have market power.

Corbae and D’Erasmo use their model of 银行业 dynamics to estimate the impact of regulatory policies on major characteristics of the banking sector. 他们雇佣你.S. 银行系统数据从呼叫报告. (受保险的银行必须每季度向美联储提交这些数据.他们的模式包含了银行业的摩擦, 包括股权发行成本, 破产成本, 政府存款保险和有限责任的存在.

作者的模型预测与美国大阳城集团娱乐网站的现有特征是一致的.S. 商业周期、银行贷款集中度和市场稳定. 此外, 他们利用自己的模型进行基于《大阳城集团娱乐网站》的反事实政策, 考虑到不完全竞争的贷款市场. Under this act, bank capital requirements rose from 4 percent (following the Basel II rules) to 8.5%(巴塞尔协议III之后).2 The authors show that a rise in capital requirements had the intended policy effect of decreasing the bank exit rate over the long run. 与此同时, 更高的资本要求减少了银行进入, 导致银行业更加集中. 进一步, the higher capital requirement incentivized big banks to strategically work over the short run to gain loan market share (which they financed by cutting dividends, 保留更多的收益, 发行更多的股票). The authors find that the net effect of more large-bank lending and less small-bank lending was a 7 percent decline in overall lending in the short run and a 9 percent decline in the long run, while the rise in the capital requirement led to only a modest rise in the interest rate on loans in the long run.3

The authors also examine how market structure affects the predictions of policy experiments. They compared a model with perfect competition to a baseline with imperfect competition in the loan market. 为了应对资本要求的提高, 他们发现, bank entry and exit rates fall much more in the long run in an imperfectly competitive market than in a perfectly competitive market. Thus, under imperfect competition, there is a lower likelihood of a banking sector crisis. The increase in capital requirements also translates into modest welfare gains in the long run in the model with imperfect competition. 与此形成鲜明对比的是, 在完全竞争, 他们发现, the change in capital requirements leads to an unintentional rise in the likelihood of a banking crisis and modest welfare losses in the long run. The authors explain the different results by pointing out that under imperfect competition, 大银行可以增加放贷，并阻止实力较弱的小银行进入这一领域, 这表明, 在这种情况下, “更多的竞争导致更脆弱.”

总之，利用他们对美国大阳城集团娱乐网站的动态模型.S. 银行业, Corbae and D’Erasmo find that regulatory policies significantly impact the banking sector’s market structure, 包括大银行的市场力量. In turn, these regulatory policies improve market efficiency and stability in the banking sector. 此外, 他们的研究表明，市场结构影响政策的有效性, indicating a potential tradeoff between the level of banking sector competition and bank stability.4

  1. The Federal Deposit Insurance Corporation (FDIC) is responsible for the criteria and standards for capital requirements, although it works in conjunction with the Federal Reserve System and the Comptroller of the Currency. FDIC rules on reserve requirements generally follow the international framework set by the Basel Committee on 银行 Supervision at the Bank for International Settlements (BIS), 这就是巴塞尔规则.
  2. 8的资本要求.5 percent consists of the minimum risk-weighted capital requirement of 6 percent plus a 2.5%的资本保护缓冲.
  3. The authors note that the interest rate response in their model depends on borrowers’ choices of financing, 这是, 银行与非银行(或“影子银行”)的贷款市场份额. 
  4. The idea of a (nonlinear) tradeoff between market concentration and stability was also discussed in David Martinez-Miera and Rafael Repullo, “竞争会降低银行倒闭的风险吗??” 财务研究检讨, 23:10 (2010), pp. 3638–3664; and in 院长Corbae and Ross Levine, “竞争, 稳定, 以及银行业的效率,“油印, 2018.