Understanding your CP12G or CP12U notice

We issue CP12G or CP12U when we correct one or more mistakes on your tax return, and

• The overpayment is different than you expected, or
• You have an overpayment when you thought you owed money or had an even balance

Call us at the toll-free number shown on your notice.

If you disagree, contact us at the toll-free number or respond by mail to the address on your notice. If you write to us, include a copy of the notice along with your correspondence or documentation.

You must contact us within 60 days of the date of your notice to request a reversal. Provide an explanation or additional documents you want us to consider when requesting a reversal. If we don't receive your supporting documents we may forward your case for audit. Audit staff will contact you within 6-12 weeks to explain the process and your rights.

If you don't contact us within the 60-day period, changes we made to reduce your refund won't be reversed and you'll lose your right to appeal our decision in the U.S. Tax Court. Instead, you may file a claim for refund to dispute the changes. Generally, you must submit the claim within 3 years from the date you filed the tax return, or within 2 years from the date of your last payment for this tax — whichever is later.