美联储抵押贷款设计、还款计划和家庭借款 2024

Mortgage Design, Repayment Schedules, and Household Borrowing

Introduction

One of the key features of mortgage contracts is the repayment schedule, which forces borrowers to gradually repay the mortgage and accumulate home equity. Historically, households had limited choices regarding repayment schedules, but recent financial innovations have introduced various alternatives, including interest-only mortgages. These alternative products allow borrowers to delay repayment, making them more flexible but also raising questions about their impact on household borrowing.

Policy Reform in Sweden

Sweden implemented a policy reform in 2016 that eliminated interest-only mortgages for borrowers with loan-to-value (LTV) ratios above 50%. This reform led to significant changes in borrowing behavior:

• Down Payments: Homebuyers increased their down payments.
• Equity Extraction: Existing borrowers reduced their equity extraction.
• Bunching: Borrowers clustered just below the 50% LTV threshold, indicating a substantial reduction in borrowing.

These changes were driven primarily by relatively wealthy households who had significant additional borrowing capacity, suggesting that credit constraints were not the primary driver.

Theoretical Framework

To understand the underlying mechanisms, the study developed a theoretical framework focusing on the psychological cost of amortization payments. The findings suggest that households experience ongoing flow disutility from amortization payments, leading them to prefer mortgages with lower initial payments even if they result in higher lifetime costs.

Empirical Analysis

The empirical analysis utilized a difference-in-bunching estimator to assess the impact of the amortization requirement. The study found significant bunching at both LTV thresholds:

• Response to Amortization Rate: New borrowers reduced their LTV ratios by 5% in response to a 1 percentage point increase in the average amortization rate.

Validity and Robustness

The study assessed the validity of its empirical approach and the robustness of its results across several dimensions, confirming that credit constraints alone cannot explain the observed behavior.

Key Findings

1. Reduction in Borrowing: The elimination of interest-only mortgages led to a 5% reduction in borrowing, driven primarily by wealthy households.
2. Psychological Cost of Amortization: Households experience ongoing disutility from amortization payments, leading them to choose mortgages with lower initial payments.
3. Increased Household Debt: New mortgage products with delayed repayment schedules may significantly increase household debt and lifetime interest costs.

Overall, the study provides strong evidence that households face "Net Present Value (NPV) neglect," prioritizing immediate affordability over long-term financial benefits.