A letter shows up from the IRS. It’s a CP2000, it mentions cryptocurrency, and it says you owe thousands more than you thought. Before you panic-sell something to cover it: a CP2000 is not an audit, and the number on it is very often wrong — usually wrong in the IRS’s favor.
Here’s what the notice actually is, why the crypto figure tends to be inflated, and how to respond without making things worse.
What a CP2000 actually is
A CP2000 is an automated underreporter notice. A computer at the IRS compared the income reported to them (1099s, including the new 1099-DA from crypto brokers) against what you reported on your return. It found a gap, did the math as if every dollar of the gap were taxable, and mailed you the bill.
No human reviewed your wallets. No agent decided you’re hiding something. It’s a matching algorithm, and matching algorithms are blunt instruments.
Why the crypto number is almost always too high
The 1099-DA your exchange filed reports your gross proceeds — the total dollar value of everything you sold or swapped. For 2025 forms, many brokers report proceeds without cost basis, especially for assets you transferred in from another wallet or exchange.
When the IRS sees proceeds with no basis, its matching system assumes the worst case: basis of zero. That treats the entire sale as gain. So if you sold 1 ETH for $3,000 that you originally bought for $2,800, the IRS may be taxing you on the full $3,000 instead of the actual $200 of gain.
Multiply that across a year of swaps and transfers and the phantom number gets large fast. The gain is real; the amount on the CP2000 usually isn’t.
The clock: you have about 30 days
The notice gives you a response deadline — typically 30 days from the date on the letter. This is the one part you cannot ignore. Miss it and the IRS issues a Notice of Deficiency and assesses the full proposed amount, after which fixing it is far more painful.
Responding on time, even just to say “I disagree, here’s why,” pauses that escalation.
How to respond
The CP2000 includes a response form where you agree, partially agree, or disagree. For most crypto cases it’s partial or full disagreement, and the response has three pieces:
- A corrected Form 8949 / Schedule D showing the real cost basis for each disposal, so the gain reflects what you actually made — not gross proceeds against zero.
- A short written explanation of the discrepancy (“broker reported proceeds without basis; corrected basis attached”).
- Supporting records — your transaction history reconciled across wallets and exchanges.
If, after correcting basis, you do still owe something, you can agree to that smaller amount. The goal isn’t to fight the IRS — it’s to make the numbers reflect reality.
What not to do
- Don’t ignore it. The deadline is real and the silence is read as agreement.
- Don’t just pay it because the letterhead is scary. You may be paying tax on gains that don’t exist.
- Don’t file an amended return as your response unless told to — a CP2000 has its own response channel, and amending in parallel can cross wires. (Amending is the right tool for catching up on something the IRS hasn’t flagged yet — different situation.)
- Don’t reconstruct basis by guessing. If it’s ever questioned, you want records that hold up, not round numbers.
When to bring in help
If the proposed balance is small and your activity was a handful of trades on one exchange, you can likely handle the response yourself. Where it gets hard — and where the inflated numbers get largest — is multi-wallet, multi-chain, DeFi, or transfers between platforms, because that’s exactly where cost basis goes missing and proceeds get double-counted.
That’s the messy middle we deal with daily: reconstructing basis across chains, reconciling it to the broker 1099-DAs, and packaging a CP2000 response the IRS can accept.
Need help with your crypto taxes? Mike Ring and the BCTP team handle the messy stuff — multi-chain DeFi, 1099-DAs that don’t add up, prior-year amendments. Free consult at cryptotaxprep.io or call 410-216-4632.
This isn’t tax advice. Talk to a professional about your specific situation.
