We argue that heightened regulation on large banks contributed to the rise in fragility of smaller banks revealed by the 2023 regional bank crisis. In 2018, regulators restricted Wells Fargo, the third largest U.S. bank, from growing its total assets. We estimate this asset cap led Wells Fargo to give up deposits amounting to 2.2% of aggregate bank deposits. These deposits, primarily uninsured, were reallocated to banks geographically proximate to Wells Fargo, including smaller, less regulated banks. In turn, these banks experienced higher deposit outflows once monetary tightening commenced and saw their stock prices plummet during the 2023 stress.

We establish that macroprudential controls limiting capital flows can curb risks arising from foreign currency borrowing by corporates in emerging markets. Firm-level data show that Indian firms tend to issue more foreign currency debt when the interest rate differential between India and the U.S. is higher. This “carry trade” relationship, however, breaks down once regulators institute more stringent interest rate caps on borrowing; in response, riskier borrowers cut issuance most. Prior to adoption of this macroprudential measure, stock price exposure of issuers to currency risk rises after issuance, as witnessed during the “taper tantrum” episode of 2013; this source of vulnerability is nullified by the measure, as confirmed during the October 2018 oil price shock and the COVID-19 outbreak. We find no evidence of the policy’s efficacy being undermined by leakage or regulatory arbitrage.