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CP2000· Underreporter (CP2000 family)

CP2000 — Automated underreporter

Automated underreporter (AUR) notice proposing changes to a tax return based on a mismatch between income or payment information reported by third parties (employers, financial institutions) and what you reported. Proposed changes may increase tax, decrease tax, or leave it unchanged.
irs.gov primary2026-05-08Form 1040-X2026-05-08
Category
Underreporter
Urgency
Date on notice
Response window
see notice
Key form
Form 1040-X

Respond by the date printed on your individual notice.

Why the IRS sent this

Mismatch between W-2 / 1099 third-party data and your filed return.

Response window

Notice received
Respond bydate on your notice

The IRS detail page for CP2000 does not state a fixed day count. The response-by date is printed on your individual notice — read the date at the top-right corner.

What to do

Required action

Review the proposed changes carefully. Complete and return the response form indicating agreement or disagreement, and include supporting documentation if disputing.

Key form: Form 1040-X — verify the current revision on irs.gov/forms-pubs before filing.

Appeal path

Informal — call the IRS

Respond informally to the AUR unit. If unresolved, a statutory notice of deficiency (CP3219A) typically follows with 90-day Tax Court petition rights. Publication 5 covers appeal rights.

Notes from the primary source

CP2000 is a proposal, not an assessment. Failure to respond typically escalates to CP3219A (statutory notice of deficiency, the 90-day letter). The IRS detail page now covers the CP2000 series collectively.

Go deeper

Educational pillars for this notice

Calm-corrective

Only the IRS can resolve your notice

We are not a CPA firm, not a law firm, not an Enrolled Agent firm, and not affiliated with the IRS. We don't accept payments on your behalf, settle your debt, or call the IRS for you. What we do: explain what your notice means, point you to the right IRS form, cite the statute that authorizes the action, and surface the appeal path. Then you call the number on the notice, file the form, or hire a licensed professional.

Related notices

Likely next or sibling codes

Source

Verified against the official IRS detail page on irs.gov/individuals/understanding-your-cp2000-series-notice. Always re-verify against the IRS page before acting.