IRS NOTICE REFERENCE
Understanding your CP28 notice
You claimed a Home Mortgage Interest Deduction on Schedule A of your 2024 Form 1040 tax return. The amount of interest you may deduct is limited by your mortgage size (outstanding mortgage amount) and date (mortgage orig…
General information only. Not legal or tax advice.
Notice details
- Notice code
- CP28
- Category
- Underreporter / income matching
- Severity tier
- Tier 2 — Action or response expected. The IRS has taken or proposed an action and expects a response or payment.
- Governing law
- §6201; §6212 (Internal Revenue Code sections)
- Source
- IRS.gov — Understanding Your IRS Notice
What this notice is
You claimed a Home Mortgage Interest Deduction on Schedule A of your 2024 Form 1040 tax return. The amount of interest you may deduct is limited by your mortgage size (outstanding mortgage amount) and date (mortgage origination date). Our records show the amount of interest that you claimed exceeds the limit. This notice has been sent to inform you of this issue and to help you verify the amount of your Home Mortgage Interest Deduction.
Source: IRS.gov. Reproduced for reference. General information — not legal or tax advice.
What the IRS says to do
Review your Schedule A, Form 1040 federal tax return for the year listed in the notice. Find important information about the Home Mortgage Interest Deduction . Verify the amount of your claim. If you claimed this deduction incorrectly: File an amended return . If you filed electronically, you may file your amended return electronically. You can get help at an IRS Taxpayer Assistance Center . Share your CP28 letter with anyone who helped you prepare your return. Verify future returns for eligibility prior to claiming the deduction. Failure to review and address any incorrect information could result in additional action from the IRS.
This is the IRS’s own guidance reproduced from the IRS notice page. It describes the IRS’s process — it is not legal or tax advice from TaxRiskOS.
Governing IRS procedure (Internal Revenue Manual)
The IRS’s own internal procedures for handling this notice type are documented in the Internal Revenue Manual:
- IRM 4.19.3 — 4.19.3 IMF Automated Underreporter Program
- IRM 4.19.2 — 4.19.2 IMF Automated Underreporter (AUR) Control
Reference to published IRS procedure. General information — not legal or tax advice.
Official IRS reference
Read the official notice page on IRS.gov: https://www.irs.gov/individuals/understanding-your-cp28-notice
Related tools
TaxRiskOS is workflow software for practitioners — it captures the notice, computes the deadline, surfaces the escalation tier, and builds a document checklist. It documents process; it does not give advice or draft responses.
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