The Rental Property Interest Deduction — Rules and Edges

Rental mortgage interest deducts fully against rental income on Schedule E — no itemizing required, no $750K home-mortgage cap, none of the personal-residence limitations. It’s the cleanest big deduction in the code, with a few edges worth actually knowing.

The clean core

Interest on debt used to acquire or improve a rental deducts against that property’s income as an ordinary expense — the deduction that makes leveraged real estate’s after-tax math work. On a typical NNN acquisition at 65% leverage, interest is the largest expense line, often converting taxable income to near zero in early years while cash flow stays positive.

The edges

Tracing rules: what you did with the money controls, not what secured it — cash-out refinance proceeds spent personally aren’t rental interest, even though the rental secures the loan; proceeds buying another investment trace to that use. Keep refinance-proceeds paper trails. 163(j) business-interest limits: mostly a big-portfolio concern — small landlords fall under the gross-receipts exemption, and larger real estate businesses can elect out at the price of slower depreciation (ADS). Worth a check above ~$30M of receipts (VERIFY current threshold). Construction-period interest: capitalized into basis, not deducted, until the asset is in service. Points and loan costs: amortized over the loan’s life, with unamortized remainders deducted at payoff or refinance-with-a-new-lender.

Planning texture

The deduction interacts with everything upstream on this site: leverage sizing on balloon structures, passive-loss caging for high earners, and exit math where accumulated interest deductions have quietly lowered basis… which is recapture’s department. Interest is simple; portfolios are not. File the clean deduction, document the tracing, and let the CPA fight the edges.