Reducing interest rates to below zero may be justified on theoretical grounds. However, in practice, it has been shown to create a number of distortions and malfunctions in several dimensions of banking system and the financial markets, which in turn may affect the whole economy. This paper surveys the theoretical grounds of unconventional monetary policy, focusing mostly on the available empirical evidence in order to provide a full picture of the impact of negative monetary policy rates. It also investigates the impact of negative interest rates on the European banking sector using a dataset of 3,155 banks from 36 European countries over the 2011–2018 period. Using a difference-in-differences methodology, we show that banks in negative interest rate environments experienced a 17.4% decrease in their net interest margins compared to banks operating in European countries that did not adopt negative interest rates. The results are found to be robust after combining propensity score matching with a difference-in-differences approach. Moreover, we find that banks that hold more liquid assets, that are highly capitalised, that have larger reserves at central banks and that take more customer deposits are more strongly affected by negative interest rates.

从理论上讲，将利率降至零以下可能是合理的。然而，在实践中，它已被证明在银行体系和金融市场的几个方面造成了一些扭曲和失灵，进而可能影响整个经济。本文调查了非常规货币政策的理论基础，主要关注现有的经验证据，以全面了解负货币政策利率的影响。它还使用 2011-2018 年期间来自 36 个欧洲国家的 3,155 家银行的数据集调查了负利率对欧洲银行业的影响。使用差异中的差异方法，我们表明负利率环境中的银行经历了 17。与在未采用负利率的欧洲国家经营的银行相比，它们的净息差下降了 4%。在将倾向得分匹配与差异中的差异方法相结合后，发现结果是稳健的。此外，我们发现持有更多流动资产、高资本化、在中央银行拥有更多准备金以及吸收更多客户存款的银行受到负利率的影响更大。