8b — Home Mortgage Interest Not on Form 1098 Updated for tax year 2025

What this line means

Mortgage interest you paid on a home loan that was not reported to you on Form 1098. This typically applies when you have a seller-financed mortgage (the seller of the home carries the loan) or a mortgage from a private individual rather than a bank. You must provide the name, address, and Social Security number of the person you paid the interest to.

Does this apply to you?

• You bought a home with seller financing and make payments directly to the seller
• You have a mortgage from a family member, friend, or private lender who did not issue a Form 1098
• You assumed a mortgage where the lender does not report interest on Form 1098

Easy to overlook

You must report the recipient’s SSN or TIN When you deduct mortgage interest not reported on Form 1098, the IRS requires you to provide the name, address, and taxpayer identification number of the person you paid. If you do not include this information, the IRS can disallow the deduction. Get a W-9 from your private lender. ¹ [SOURCE: IRS Schedule A instructions — Line 8b]

The same $750,000 debt limit applies Seller-financed mortgages are subject to the same $750,000 total mortgage debt limit as bank mortgages. The source of the loan does not change the deduction cap. If your seller-financed mortgage exceeds $750,000, only the interest on the first $750,000 is deductible. ² [SOURCE: General filing pattern — seller-financed mortgage interest deduction]

Watch out for this

Claiming the deduction without providing the lender’s taxpayer identification number. The IRS specifically requires this information when there is no Form 1098 to match against. Omitting it is a red flag that can trigger a notice or disallowance of the deduction. Attach a statement with the lender’s name, address, and TIN.

Related lines on your return

• Line 8a — Schedule A — Mortgage interest from Form 1098 (bank and institutional lender interest)
• Line 10 — Schedule A — Total interest paid
• Line 2b — Form 1040 — Taxable interest (the lender receiving your payments reports it here on their return)