We are just about finished with the August economics marathon.
In my earlier post Economics 202: Artificial Limits on Supply – Housing, I argued that one factor leading to the ever-increasing cost of housing was government actions, such as zoning restrictions, that tend to limit supply. Another government program, the mortgage interest deduction,((just in case the reader is not certain what the mortgage interest deduction is: in general, a taxpayer who itemizes deductions may deduct from adjusted gross income the interest paid on money borrowed to buy or improve the taxpayer’s residence, so long as the loan is secured by a mortgage on the property.)) acts as a demand-side subsidy((The mortgage interest deduction is what is sometimes called a “tax expenditure,” which means that the government does not actually incur an expense but foregoes revenue, which has the same effect.)) and contributes to the increase in housing costs.
“Wait,” you may say, “I thought the mortgage interest deduction benefits homebuyers and makes buying a house more affordable.” I long thought so myself and supported the mortgage interest deduction as a way to encourage home-ownership. However, I have recently concluded, consistent with the earlier examples of the effects of demand-side subsidies, that it does not really work that way. When a homebuyer (and her lender) is calculating the mortgage amount she can afford (which, when added to the down payment, is, less closing costs, the maximum she can pay for a house) she is looking at the monthly payment. The deductibility of mortgage interest means that the mortgage payment can be that much higher, increasing the gross amount that can be paid in debt service and therefore the amount that can be borrowed. In a seller’s market, the buyer will be forced to the upper edge of her affordability envelope (if she does not choose to go there, one of the other potential buyers certainly will). Thus, the true beneficiary of the mortgage interest deduction is the home seller.
Because I do not believe that there is any general social benefit to using a tax expenditure to keep housing costs as high as they are, I have concluded that the mortgage interest deduction should be discontinued. Because, however, millions of homeowners took the deductibility of mortgage interest into account in determining how much to borrow, it could be catastrophic (and certainly would be unfair) to take the deduction away all at once. I would like to see it ratably reduced over a span of 25 or 30 years.((Under the 25-year plan, in year 1 96% of mortgage interest (including new mortgages) would be deductible, in year 2 92% and so on until zero deductibility is achieved in year 25.))
Jay Bohn
August 30, 2021