A Simple Model of Subprime Borrowers and Credit Growth
构建了一个包含优质和次级借款人的简单模型，解释了信贷供给扩张时次级借款人债务增长更快、房价上涨更显著的现象，对理解金融危机前信贷繁荣有参考价值。
The surge in credit and house prices that preceded the Great Recession was particularly pronounced in ZIP codes with a higher fraction of subprime borrowers (Mian and Sufi, 2009). We present a simple model with prime and subprime borrowers distributed across geographic locations, which can reproduce this stylized fact as a result of an expansion in the supply of credit. Due to their low income, subprime households are constrained in their ability to meet interest payments and hence sustain debt. As a result, when the supply of credit increases and interest rates fall, they take on disproportionately more debt than their prime counterparts, who are not subject to that constraint.