This paper proposes a novel explanation for why foreign currency denominated loans to households have become so popular in some emerging economies. Our argument is based on what we call the debt limit channel, which arises when multi-period contracts are offered against collateral that is established on newly acquired assets. Whenever the difference between domestic and foreign interest rates is positive, this effect allows financially constrained agents to backload the real payments on their loans if they choose to borrow in foreign currency. We demonstrate in a structural macroeconomic framework that the debt limit channel is quantitatively important and can result in dollarization of debt despite realistic and correctly perceived exchange rate risk. Comparing this outcome to allocations under constrained-optimal policy reveals that much of the identified bias towards foreign currency is due to a pecuniary externality, i.e. borrowers' failure to internalize how their currency choice affects house prices.

本文提出了一个新颖的解释，解释为什么外币计价的家庭贷款在一些新兴经济体如此受欢迎。我们的论点基于我们所说的债务限额渠道，当针对新收购资产的抵押品提供多期合同时，就会出现这种渠道。每当国内和国外利率之间的差异为正时，如果选择以外币借款，这种影响允许财务受限的代理人将其贷款的实际付款倒退。我们在结构性宏观经济框架中证明，尽管存在现实和正确感知的汇率风险，但债务限额渠道在数量上很重要，并且可能导致债务美元化。