Banks use trading as a vehicle to take risk. Using high-frequency regulatory data, we estimate the sensitivity of weekly bank trading profits to aggregate equity, fixed-income, credit, currency, and commodity risk factors. Our estimates imply that U.S. banks had large trading exposures to equity market risk before the Volcker Rule, which they curtailed afterwards. Credit and currency risk exposures were smaller. The results hold up in a quasi-natural experiment that exploits the phased-in introduction of reporting requirements for identification. Total trading-book risk was also curtailed afterwards with material financial stability implications and no evidence of migration to other bank activities.

中文翻译：

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银行作为受监管的交易商

银行将交易作为承担风险的工具。使用高频监管数据，我们估计了每周银行交易利润对股票、固定收益、信贷、货币和商品风险因素的敏感性。我们的估计表明，美国银行在沃尔克规则之前就存在大量的股票市场风险敞口，之后它们又减少了这种风险敞口。信用和货币风险敞口较小。结果在一个准自然实验中成立，该实验利用了分阶段引入身份识别报告要求。其后，总交易账簿风险也得到了降低，这严重影响了金融稳定，并且没有证据表明其转移到其他银行活动。