New Mortgage Data Reveals Sharp Affordability Drop in Major US Housing Markets
Washington, Monday, 2 March 2026.
Using actual loan data, a new index confirms 42 of 50 top markets are less affordable, with Boston down payments now demanding 96.2% of a borrower’s annual income.
A Data-Driven Reality Check
On March 2, 2026, Polygon Research released the Polygon Affordability Index (PAI), a comprehensive new metric that challenges traditional market assessments by utilizing actual loan-level data rather than listing prices [1]. The index’s findings are stark: between 2018 and 2024, affordability deteriorated in 42 of the 50 largest housing markets in the United States [1]. Unlike standard indices that rely on median assumptions, the PAI is constructed from the complete Home Mortgage Disclosure Act (HMDA) dataset, allowing it to capture the specific financial realities of borrowers across over 82,000 census tracts [2]. Greg Oliven, Chief Technology Officer at Polygon Research, emphasizes that this approach reflects the “lived experience of real borrowers in actual transactions” rather than hypothetical market conditions [1].
Methodology and Market Mechanics
The PAI evaluates affordability on a scale of 0 to 100, where a higher score indicates greater affordability [2]. The scoring model is weighted to reflect the primary financial stressors on homebuyers: 50% is attributed to payment burden, 30% to price burden, and 20% to down payment burden [1][2]. By focusing on fixed-rate, first-lien, closed-end purchase loans for 1–4 family primary residences, the index filters out speculative noise and high-end outliers, specifically excluding transactions with property values or applicant incomes exceeding $100 million [1][2]. This rigorous methodology provides a consistent view of the market’s structural health from 2018 through the present day [1].
Regional Disparities and Financial Strain
The data highlights severe purchasing power erosion in key metropolitan hubs. In 2024, Seattle ranked as the least affordable major housing market, with monthly mortgage payments consuming 26.6% of borrower income, a significant rise from 20.8% in 2018 [1]. Consequently, Seattle’s PAI score fell 5.3 points to 47.4 over this period [1]. Boise experienced the sharpest overall decline, with its score dropping 8.5 points to 52.9; this was driven by a down payment burden that surged from 61.5% to 87.2% of annual borrower income [1]. The Northeast also faces critical barriers to entry, with Boston’s down payment burden reaching 96.2% of annual borrower income in 2024 [1].
Contrasting Market Trajectories
While the prevailing trend is negative, the data reveals divergent paths for different regions. Rust Belt cities have not been immune to the downturn; Cleveland saw its affordability score drop by 6 points to 72, and Pittsburgh declined by 5 points to 72 [2]. Conversely, Los Angeles defied the national trend, recording a modest improvement as its PAI score rose 4 points to reach 54 [2]. These shifts are occurring against a backdrop of rising loan limits, with counties like Anderson County, Texas, seeing conventional loan limits reach $832,750 in 2026 to accommodate inflating asset prices [5].
Broader Economic Signals
The tightening of residential affordability parallels complex signals in the commercial real estate sector. Cushman & Wakefield reported fourth-quarter revenue of $2.91 billion for the period ending in 2025, a 10.8% year-on-year increase that beat analyst expectations [3]. While the firm’s leasing and capital markets revenues have grown, its management revenue has seen declines over the last two years, reflecting a volatile environment for real estate services [3]. Looking ahead, industry leaders are turning to technology to navigate these headwinds. The Mortgage Bankers Association is set to convene on May 14, 2026, to discuss how AI-driven innovation and next-generation loan origination systems can streamline operations in this shifting economic landscape [4].