According to HousingWire, mortgage lenders have become quite skilled at measuring the risk that borrowers pose to them, looking at credit scores, debt levels, and property values. Yet the industry has largely overlooked something fundamental: the enormous risk that homeowners themselves face by concentrating most of their wealth into a single property. This is economically similar to an investment adviser recommending that someone put most of their net worth into one stock, which would be considered reckless in any other financial context.
When a homeowner's individual property declines substantially in value, the homeowner becomes more vulnerable financially, not just to the lender but in real terms. The homeowner's equity shrinks, their ability to move becomes limited, and refinancing becomes harder. What might otherwise be a manageable income disruption can turn into a genuine financial crisis. The article points out that when a homeowner's financial health deteriorates, mortgage credit performance typically follows, suggesting that protecting homeowners from concentration risk might also reduce the credit risk that lenders face.
To test this theory, researchers examined data from over one million mortgages originated by Freddie Mac between 1999 and 2020. They modeled what would happen if homeowners could diversify their exposure to a single property's performance. The results were striking. Traditional mortgages showed modeled expected credit losses of roughly 29 to 30 basis points, while a diversified structure with zero down payment showed expected losses of roughly 5 to 6 basis points. This suggests that diversification, a fundamental principle in finance, could significantly reduce mortgage credit risk.
The article raises an important historical point about the Great Financial Crisis. Leading up to 2006, subprime and Alt-A mortgages made up nearly 39 percent of all new mortgage originations, largely because the industry tried to address housing affordability by increasing leverage rather than by reducing homeowner risk. The author suggests that if diversified mortgage structures had been available at scale, the foreclosure crisis might have looked very different, even if it could not have been prevented entirely.
The current approach to housing affordability typically involves lower down payments, subsidies, mortgage insurance, longer repayment periods, or relaxed credit standards. These tools can help households purchase homes, but they do not actually reduce the concentration risk that comes with owning a single property. Some approaches even increase leverage while leaving the homeowner's underlying investment risk unchanged. A diversified mortgage structure would work differently by offsetting some of the homeowner's losses if their specific property underperforms compared to a broader housing benchmark, while still allowing them to benefit if their property outperforms.
What I am seeing locally here in the Bay Area and East Bay is that the conversation around affordability needs to shift beyond just making the mortgage payment manageable at closing. For buyers and sellers alike, the real question should be whether homeownership remains financially sustainable over time, especially in a region where property values can swing dramatically. If these diversified structures could be implemented responsibly, it might offer a genuinely different path forward for qualified households looking to build wealth through homeownership without betting their entire financial future on a single property.
