The secular decline in interest rates and the rise of shadow banks

• 成果类型: Article
• 署名作者: Sarto, Andres; Wang, Olivier
• 刊物名称: JOURNAL OF FINANCIAL ECONOMICS
• ISSN/ISSBN: 0304-405X
• DOI: 10.1016/j.jfineco.2025.104228
• 发表日期: 2026-03
• 页码: 104228
• 关键词: Low interest rates; Net interest margin; Shadow banks; Non-banks; mortgages; monetary-policy; transmission; TECHNOLOGY; channel; credit

摘要

Over the past two decades, shadow banks have significantly expanded their share of residential mortgage lending, even surpassing pre-financial crisis levels. This surge is often attributed to post-crisis regulatory changes and improvements in shadow banks' technology. In this paper, we document a new driving force: the persistent decline in interest rates. When interest rates are high, cheap deposit funding provides banks with a significant competitive advantage against shadow banks relying on wholesale funding. As interest rates plummet and approach the zero lower bound, banks lose this advantage, experience a squeeze in their net interest margin, leading to diminished profitability, weaker growth, and cost-cutting measures such as branch closures. By contrast, shadow banks are able to gain market share. We test this mechanism using a shift-share empirical design based on differences in historical bank balance sheet composition. We find that banks more vulnerable to falling interest rates contracted lending as a response to lower profitability while also scaling back non-interest expenses on their branches. This created a fertile environment for non-banks to expand in areas with banks exposed to declining interest rates.