The mortgage interest deduction is one of the most politically untouchable provisions in the US tax code. Politicians from both parties defend it as support for hardworking homeowners and the bedrock of the American Dream. The branding is excellent. The economics are not.
In practice, the deduction is a regressive transfer that delivers most of its benefits to high earners with large mortgages, distorts housing markets, and offers little help to the people most strained by housing costs.
Most homeowners don’t even use it
After the 2017 tax law nearly doubled the standard deduction, the share of taxpayers itemizing collapsed. Joint Committee on Taxation analyses now show fewer than 15 percent of households claim mortgage interest at all. The remaining users skew sharply toward the top of the income distribution because they have larger mortgages, higher state and local taxes, and incomes high enough to make itemizing worthwhile. A typical middle-income homeowner with a modest mortgage takes the standard deduction and gets nothing extra from owning. The “homeowner subsidy” is, on the data, a subsidy for people whose homes are already comfortable enough to be expensive.
It inflates housing prices, not ownership
Decades of research from the Tax Policy Center, Wharton, and the Federal Reserve find that the deduction does almost nothing to increase the homeownership rate. What it does instead is push prices upward, particularly in high-cost metros where buyers can capitalize the tax savings into bigger bids. That bidding war benefits sellers — current owners — while raising the entry barrier for first-time buyers. Countries that eliminated similar deductions, including the UK and Canada, saw no decline in homeownership rates, undermining the central political defense of the policy. The deduction makes existing owners richer without expanding access.
The opportunity cost is enormous
The deduction costs roughly $25 to $30 billion per year in foregone federal revenue, even after the 2017 cap. That money could fund first-time buyer assistance, expand Low-Income Housing Tax Credits, or be returned as a broader credit available to renters and owners alike. Instead, it flows automatically toward households who already own large homes in expensive zip codes. Economists across the political spectrum — from the Center on Budget and Policy Priorities to the conservative American Enterprise Institute — have long described the deduction as poorly targeted and inefficient. It survives not because it works but because it has a powerful constituency that benefits visibly while the costs are diffuse.
The bottom line
If the mortgage interest deduction were proposed today as a new program — “send a check averaging several thousand dollars per year to upper-middle-class homeowners with large mortgages” — it would be laughed out of any serious policy room. It exists because it was grandfathered in, then defended by a real-estate industry that profits from inflated prices. Honest tax reform would phase it out and redirect the money to housing access tools that actually work: down-payment assistance, supply-side construction incentives, and a refundable credit available to renters. Until then, the deduction will keep being what it is — welfare for people who already won the housing market.
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