A letter shows up from the IRS, usually a year or more after the return it's about was filed. It's not an audit notice and it doesn't look like a bill — it's titled CP2000, it proposes an amount of additional tax, and it says the IRS's own records don't match what was reported. For a reseller who got a 1099-K from eBay, Shopify, or Discogs that year, this is one of the more common notices to land in the mailbox, and the instinct to just pay what it asks for is often the wrong move.
What a CP2000 actually is
The IRS runs an automated matching program — the Automated Underreporter (AUR) system — that cross-checks the income and payments reported on a filed Form 1040 against the third-party information returns the IRS separately received for that same year: W-2s, 1099-NEC, 1099-K, 1098, and others. When a number on one of those forms doesn't appear to be accounted for on the return, AUR generates a CP2000 proposing an adjustment.
The IRS's own description of the notice is specific on two points worth holding onto: it is not a bill, and it is not the start of a formal audit. It's a proposed change based on a computer match, and the taxpayer gets to agree, partially agree, or disagree before anything is actually assessed. The notice prints its own response deadline — commonly 30 days from the notice date (60 if the recipient lives abroad) — and that date, not a general rule of thumb, is the one that matters for a specific notice in hand.
Ignore it past the deadline and the IRS doesn't just drop it: the next step is a CP3219A, a Statutory Notice of Deficiency, which formally proposes the assessment and explains the right to petition U.S. Tax Court before it becomes final. Responding to the CP2000 itself — agreeing, or explaining the gap with documentation — is the step that heads that off.
Why resellers trip this match specifically
The mechanical trigger is almost always the same thing this blog has covered from the other direction: a 1099-K's Box 1a reports gross payment volume — the full amount a platform processed before fees, refunds, or shipping come out — and AUR is checking whether that gross number shows up somewhere in what was reported, not whether net profit looks reasonable.
The usual way a reseller ends up with a mismatch isn't hidden income. It's a Schedule C filled out backward: reporting net profit on the gross receipts line (Line 1) after quietly subtracting fees and cost of goods sold in their head, rather than reporting the full gross receipts figure on Line 1 and then taking fees, shipping costs, and COGS as separate expense lines further down the form. The structure exists for exactly this reason — gross receipts up top, deductions below — and skipping it is what makes the 1099-K's gross figure look like unreported income to a system that's only matching gross against gross.
A seller who nets everything together before it ever reaches the return can owe exactly the right amount of tax and still get a CP2000, because the number AUR is looking for was never written down anywhere on the form, even though its effect was accounted for in the final profit figure.
What the notice actually proposes, and the three ways to respond
A CP2000 lays out, line by line, the difference between what a given 1099 or W-2 reported and what AUR thinks should have shown up on the return, along with the additional tax, penalties, and interest that difference would produce if accepted as-is. The response options are:
- Agree. Sign and return the response form by the deadline. This
- doesn't require filing an amended return — the notice itself is the
- mechanism for assessing the change. Paying in full by the deadline stops
- additional interest from accruing; a balance can also go on a payment
- plan (Form 9465) if paying in full isn't realistic.
- Disagree, in part or in full. Attach a written explanation and
- supporting documentation — your own Schedule C, the 1099-K itself, and
- the order-level records that reconcile the two — and send it by the
- method printed on the notice (upload, fax, or mail to the address in the
- top corner).
- Do nothing. Functionally the same as agreeing, except without the
- chance to correct a wrong computer match: the proposed amount moves
- toward assessment on its own timeline, headed for a CP3219A if the
- deadline passes.
For the reseller case above — net profit on Line 1 instead of gross receipts — "disagree" doesn't mean disputing that any tax is owed. It means showing the IRS the same income, correctly structured: gross receipts matching the 1099-K, with fees, refunds, and cost of goods sold broken out as the deductions they actually are. The total tax owed is often unchanged or close to it; what changes is whether the return on file matches the form AUR is comparing it against.
What to actually pull together
- Get the specific 1099-K the notice is referencing, not a guess at
- what it should say. If it's missing, a Wage and Income Transcript from
- the IRS (online, or via Form 4506-T) shows exactly what was reported
- under your SSN or EIN for that year.
- Reconcile it against your own order-level log, the same exercise [this
- blog has walked through for eBay payouts](/blog/ebay-payout-reconciliation-2026)
- — sale price, shipping collected, refunds, fees, and COGS, order by
- order, not estimated in aggregate.
- Don't file an amended return as the response if you're agreeing — the
- CP2000 response form is the correct channel; an amended return filed on
- top of an open CP2000 tends to create a second, separate problem rather
- than resolving the first.
- Authorize a preparer with Form 2848 if you want a CPA or enrolled
- agent handling the response directly with the IRS, rather than relaying
- paperwork back and forth yourself.
- Call the number on the notice if you need more time — extensions are
- sometimes granted, but they're not guaranteed, and the request has to
- happen before the printed deadline, not after.
None of this is a reason to panic about a 1099-K arriving at all. The 2026 threshold for a platform to issue one is back to $20,000 and 200 transactions — this blog covered the reversal when it happened — so plenty of sellers won't get a form at all this year. That cuts both ways: no 1099-K means no CP2000 built off of one, but it has zero bearing on whether the underlying income is taxable. AUR only flags mismatches against forms the IRS actually received; it was never a mechanism for deciding what counts as income in the first place.
PalmFlow keeps the order-level detail this kind of reconciliation actually needs — sale price, fees, refunds, and cost basis — for every order synced from eBay, Shopify, or Discogs, so a notice like this gets matched against real numbers instead of a year reconstructed from memory. That data is there on every plan, free included (50 active items, no card required); the formatted Schedule-C-style summary built on top of it is a Pro feature.
Disclaimer: this is general information, not tax advice. CP2000 procedures, response deadlines, and 1099-K thresholds are set by the IRS and can change — read the specific notice you received carefully, verify current details against IRS.gov, and talk to a CPA or enrolled agent before responding to an actual notice.