Monetary policy, DTI, race: Key factors in mortgage denial
A Federal Reserve Bank of St. Louis working paper analyzes 30 million mortgage applications from 2018–2024, identifying monetary policy, debt-to-income ratios, and racial disparities as key determinants of mortgage denial.
Three drivers of mortgage denial
The study establishes three primary findings on mortgage denial.
First, credit access is highly sensitive to monetary policy; the 2022–2023 tightening cycle increased aggregate denial rates from 12.2 percent to 15.7 percent, primarily through the debt-to-income (DTI) channel.
Second, a critical nonlinearity exists in underwriting: while the 43 percent qualified mortgage (QM) threshold is non-binding, denial rates jump by 15–17 percentage points at the 50 percent DTI mark, which functions as the true market boundary.
Third, substantial racial disparities persist, with Black applicants 7.8 percentage points more likely to be denied than White applicants, even after controlling for lender fixed effects and financials.
Observable characteristics explain at most 41 percent of this gap.
This demonstrates how monetary tightening interacts with structural inequalities to disproportionately restrict credit access for vulnerable populations.
HMDA data reveals underwriting nuances
The researchers leveraged over 30 million home purchase mortgage applications from 2018–2024, utilizing publicly available Home Mortgage Disclosure Act (HMDA) data.
This dataset, enhanced by Dodd-Frank Act mandates from 2018, provides granular insights into underwriting decisions, including debt-to-income (DTI) ratios, combined loan-to-value (LTV) ratios, and specific denial reasons.
The study focuses on home purchase mortgages, crucial for homeownership entry.
Mortgage denial rates are highly cyclical, synchronizing with interest rates.
The aggregate denial rate rose from 12.2 percent in 2021 to 15.7 percent by 2023 during aggressive monetary tightening.
DTI is the most frequently cited reason for denial, accounting for 35 percent of all rejected applications.
Unequal access, policy blind spots
This research offers a critical lens on the practical efficacy of mortgage regulations, revealing that the statutory QM threshold of 43 percent DTI is largely ineffective as a binding constraint.
The market's functional boundary at 50 percent DTI demands closer policy attention, especially as monetary tightening disproportionately impacts vulnerable groups.
Persistent, unexplained racial disparities underscore deep-seated structural issues in credit access.