Mortgage Interest Deduction Under OBBBA

August 17th, 2025 at 7:08 AM

If you deduct mortgage interest, the One Big Beautiful Bill Act (OBBBA) brings some important updates.

First, it permanently caps the mortgage interest deduction for interest on up to $750,000 of acquisition debt ($375,000 if married filing separately). Interest on home equity loans remains deductible only if the loan is used to improve your home—and stays within that cap.

Starting in 2026, you may also deduct mortgage insurance premiums—but only if your AGI is under $100,000 (filing jointly) or $50,000 (filing separately). Above that, the deduction phases out quickly.

Homeowners with grandfathered debt predating December 16, 2017, still benefit from the higher $1 million cap.

Mark S. Fineberg, CPA