Missing stock or crypto basis
Reconstruct acquisition cost and sales, then provide the corrected gain or loss calculation.
The IRS found a mismatch between your return and third-party records. The proposal may be right, partly right, or missing critical context.
A guide by Taxstra Tax & Accounting — CPA-led tax strategy for business owners
Written by Bryan Martin, CPA, Managing Partner and Founder of Taxstra. Last updated July 10, 2026.
Quick answer
A CP2000 is an automated-underreporter proposal based on differences between your return and information reported by employers, banks, brokers, or other payers. It is not a bill or a full audit. Respond by the date shown after checking basis, duplicate reporting, corrected forms, and every related deduction.
Computer matching finds differences; it does not reconstruct the whole transaction
The IRS compares filed returns with Forms W-2, 1099, K-1, and other information returns. CP2000 explains a proposed change when those records appear not to match.
The proposal can overstate tax when gross stock or crypto proceeds are treated without cost basis, income appears in a different location on the return, a payer used the wrong taxpayer identification number, or the same income was reported twice.
If the IRS is correct, the response should still check whether its calculation includes every connected expense, credit, withholding payment, and penalty issue. If it is wrong, the response should explain each disputed item and attach records that let a reviewer reproduce the correction.
Gross proceeds are not automatically taxable income.
A broker may report the amount sold while basis determines the gain. The response must show the full transaction, not simply say the IRS number is wrong.
Read the current IRS explanation for this notice at IRS.gov. The instructions and address printed on your own letter control.
Protect the deadline before solving the whole case
Respond by the date printed on CP2000
The IRS instructs recipients to respond by the notice date shown. If more time is needed, follow the current extension instructions before the response period expires; do not assume an extension was granted.
Make the reviewer’s calculation easy.
Use a short cover letter, an item-by-item reconciliation, and labeled exhibits. A pile of statements without a bridge to the disputed number is not a persuasive response.
The strongest response is precise about each proposed item
Agree only after confirming the arithmetic and the complete tax effect. Partial agreement is appropriate when some information items are correct and others need adjustment.
When you disagree, identify the payer, form, amount shown by the IRS, amount that should be used, and supporting exhibit. If identity theft or a payer error is involved, follow the notice-specific documentation process.
Reconstruct acquisition cost and sales, then provide the corrected gain or loss calculation.
Map where the income already appears on the return and attach the relevant schedule.
Request a corrected form or payer statement and tell the IRS if that correction is pending.
Confirm the full calculation, consider penalty grounds, and arrange payment if needed.
A useful response is built from records, not reassurance
Avoid the predictable failure points
Amending reflexively instead of following CP2000
Use the response instructions on the notice. An amended return may be appropriate in some cases, but it is not a substitute for answering the open notice.
Agreeing because the payer form looks official
Information returns can omit basis, contain errors, or duplicate income. Reconcile them to the return.
Responding without a signed explanation
Follow the notice instructions for signatures, response forms, supporting records, and delivery.
Some letters are administrative; others put real rights or assets at risk
CP2000 representation is most valuable when the proposed tax is material or the response requires reconstructing transactions rather than sending one missing form.
Taxstra can review the notice, reconcile it to the return and IRS records, and handle authorized IRS contact through our notice defense service. If the letter is part of a larger unpaid-tax problem, see our tax relief service.
We can reconcile the information returns, rebuild basis and expenses, prepare the response, and handle authorized IRS contact.
Book a free 30-minute call to walk through your situation. We'll tell you exactly how our CPA-led team can help — and whether we're the right fit.