A crypto tax audit usually starts with a letter, not a knock on the door. The IRS matches what exchanges report (now on Form 1099-DA) against your return. It also uses court-approved “John Doe” summonses for exchange records and the digital-asset question on Form 1040 to spot gaps. If you get Letter 6173, you must respond by the deadline. Letters 6174 and 6174-A are warnings, and a CP2000 proposes extra tax. The best defense is complete records and fixing errors yourself before the IRS finds them. This is general information, not tax or legal advice.
- Brokers began reporting customers’ gross proceeds from digital asset sales on Form 1099-DA for 2025 transactions, which makes mismatches easy for the IRS to find automatically.
- Letter 6173 requires a signed response by the deadline. Letters 6174 and 6174-A are educational and need no reply, but you should still fix any errors.
- A CP2000 is a proposed adjustment, not an audit. You can agree, partly agree or dispute it.
- The IRS generally has three years to assess extra tax, six if you left out more than 25% of your gross income, and no time limit if you never filed or committed fraud.
- Amending before the IRS contacts you usually costs far less than waiting.
How the IRS finds crypto income
Crypto isn’t anonymous to the IRS. Its information comes from several sources:
- Form 1099-DA. Under the broker reporting rules, US custodial platforms report customers’ gross proceeds from digital asset sales starting with 2025 transactions, and cost basis for “covered” assets acquired from 2026 onward. Proceeds reported without matching entries on your Form 8949 are exactly what the IRS’s matching system flags. (A separate rule that would have extended reporting to DeFi front-ends was repealed by Congress in April 2025.) Our Form 1099-DA guide explains what’s on the form and why the reported basis can be wrong after transfers between platforms.
- John Doe summonses. Courts have let the IRS demand records on whole groups of exchange customers without naming them. Coinbase (2016, later narrowed to accounts with at least $20,000 of activity), Kraken (authorized in 2021 for customers with at least $20,000 in transactions between 2016 and 2020), Circle, and SFOX and its banking partner (2022) all received one. The Justice Department said these petitions didn’t allege wrongdoing by the exchanges. They target taxpayers who didn’t report.
- The digital-asset question. Forms 1040, 1040-SR and 1040-NR ask whether you received, sold, exchanged or otherwise disposed of a digital asset. Ticking “No” when records show sales can be used as evidence the omission wasn’t an innocent mistake.
- Older 1099s and blockchain analytics. Some exchanges issued 1099-K or 1099-MISC forms in earlier years, and the IRS uses chain-analysis tools to trace funds once it has a starting address.
IRS crypto audit letters: what each one means
The IRS first used its “virtual currency” letters in 2019, when it said it was sending them to more than 10,000 taxpayers. The letter numbers are still in use, and they’re far from the same thing:
| Notice | What it says | Response required? | What to do |
|---|---|---|---|
| Letter 6174 | Educational: you may have crypto transactions and should check you reported them | No | Review your returns and amend if anything is missing |
| Letter 6174-A | Stronger wording: the IRS believes you may not have reported correctly | No, but treat it as a warning | Same as above; future enforcement is possible |
| Letter 6173 | The IRS has information that you may not have reported crypto, and asks you to explain or correct it | Yes, by the date on the letter | Respond in writing (signed, often under penalty of perjury), with an amended return or an explanation |
| CP2000 | Automated mismatch between third-party reports (like a 1099-DA) and your return; proposes extra tax, interest and possibly penalties | Yes, by the response date | Agree, partly agree, or dispute with documentation such as cost basis |
| Examination (audit) letter | Formal notice that your return is selected for a correspondence or field audit | Yes | Gather records; strongly consider professional representation |
A common CP2000 situation: the 1099-DA shows only gross proceeds with no basis (normal for coins bought before 2026 or transferred in from elsewhere). The IRS computer treats the whole amount as gain. Supplying your actual purchase records usually brings the proposed tax down sharply.
Watch for fake IRS crypto letters
Scammers send letters and emails imitating the IRS that use QR codes or links to a made-up “digital asset compliance portal” and ask for wallet details or payment. The real IRS doesn’t ask for seed phrases or private keys. Check any notice by calling the number on the IRS’s own website or logging in to your IRS online account, never through a link or QR code in the letter.
Crypto audit risk: common red flags
The IRS doesn’t publish its selection formulas, but these patterns tend to cause problems:
- 1099-DA proceeds with no matching Form 8949 entries. This is the most mechanical trigger and the easiest to avoid.
- Answering “No” to the digital-asset question while an exchange reports activity in your name.
- Large deposits to a bank account from an exchange with no matching income or gains reported.
- Unreported staking, mining or airdrop income. These are ordinary income when received, separate from capital gains.
- Big losses with thin documentation, including theft or scam losses claimed without meeting the legal tests.
- Inconsistent cost basis methods from year to year, or basis figures that can’t be traced to purchase records.
How sales are taxed in the first place (short- versus long-term rates, holding periods) is covered in our guide to capital gains tax on crypto.
What happens if you don’t report crypto?
The consequences rise with how much you left out and whether it looks deliberate:
- Tax plus interest on the underpayment, running from the original due date.
- Accuracy-related penalty: generally 20% of the underpayment caused by negligence or a substantial understatement.
- Failure-to-file penalty if no return was filed: 5% of unpaid tax per month, up to 25%.
- Civil fraud penalty: 75% of the underpayment attributable to fraud.
- Criminal prosecution is rare and reserved for willful evasion, but crypto cases do get prosecuted.
Time limits matter too. The IRS generally has three years from filing to assess more tax. That stretches to six years if you left out more than 25% of the gross income on your return, and there’s no limit if you never filed or the return was fraudulent. So “it was years ago” doesn’t always protect you.
How to respond to a crypto tax audit or IRS notice
- Read the notice type and deadline first. Put the response date in your calendar. If you need more time, ask for it before the deadline, not after.
- Rebuild your transaction history. Export complete CSVs from every exchange and wallet you used, including closed accounts if you can still get them. Import them into crypto tax software to reconcile transfers between your own wallets, which are not taxable sales.
- Compare against what the IRS has. Line up the 1099-DA or the figures in the notice with your reconstructed gains. Missing basis is the most common fixable gap.
- Answer only what’s asked, in writing, with organized supporting documents. Keep copies of everything you send and note how and when it was sent.
- Don’t sign a 6173 response or audit agreement you don’t understand. Statements may be made under penalty of perjury.
- Get representation for anything beyond a simple mismatch. An enrolled agent, CPA or tax attorney can deal with the IRS for you. Our guide to choosing a crypto tax preparer covers which credentials matter. If criminal exposure is possible, start with a tax attorney, because attorney-client privilege applies.
Amended returns and voluntary disclosure
If you find unreported crypto before the IRS contacts you, the usual route is an amended return on Form 1040-X for each affected year, with corrected Form 8949 and Schedule D, and payment of the tax and interest. Correcting errors on your own generally puts you in a far better position on penalties than waiting for a notice.
For deliberate non-compliance where criminal exposure is a real concern, the IRS Criminal Investigation Voluntary Disclosure Practice exists (it begins with Form 14457). It comes with its own penalty framework and requirements, and it isn’t something to try without an attorney. The IRS digital assets page on irs.gov is the authoritative source for current reporting rules and forms.
Record-keeping that survives an audit
A crypto tax audit mostly comes down to whether you can document basis and dates. Keep, for at least as long as the statute of limitations (longer for coins you still hold):
- Exchange trade histories and annual statements, exported every year in case a platform shuts down or limits access.
- Wallet addresses you control, and notes linking transfers between your own accounts.
- Records of the fair market value on the date you received staking rewards, airdrops or crypto income.
- Your tax software reports and the cost-basis method you used.
- Dates of any loss-harvesting sales and buybacks. As of October 2026 the wash-sale rule doesn’t apply to crypto, because crypto is treated as property. However, H.R. 10357, the Digital Asset Tax Certainty Act, cleared the House Ways and Means Committee on September 16, 2026, and as drafted would apply wash-sale rules to digital assets sold after September 14, 2026. It is not law unless both chambers pass it and it’s signed, but clean records protect you either way.
Our broader crypto tax guide covers how each kind of transaction is taxed, and the bitcoin guides hub collects related how-tos.
FAQ
Does the IRS audit crypto?
Yes. The IRS has run crypto-specific letter campaigns since 2019, obtained customer records from major exchanges through court-approved John Doe summonses, and now gets broker-reported proceeds on Form 1099-DA. Most contacts begin as automated notices (CP2000) or letters (6173, 6174, 6174-A) rather than full audits, but unresolved notices can lead to formal examinations.
What is IRS Letter 6173?
Letter 6173 tells you the IRS has information suggesting you may not have properly reported virtual currency transactions, and it asks you to respond by a set date, either by filing or amending returns or by explaining why your reporting was correct. Unlike Letters 6174 and 6174-A, it requires an answer. Ignoring it can lead to an examination.
What happens if you don’t report crypto on your taxes?
You can owe the unpaid tax plus interest and penalties: commonly 20% for accuracy-related underpayments, up to 25% for failing to file, and 75% where fraud is shown. Willful evasion can be prosecuted. The IRS usually has three years to assess more tax, six for large omissions, and unlimited time for fraud or unfiled returns.
How do I lower my crypto audit risk?
Report every taxable sale on Form 8949 so it matches broker 1099-DA filings, answer the digital-asset question accurately, report staking and airdrop income, and keep full transaction exports with cost basis. Reconcile transfers between your own wallets so they aren’t mistaken for sales. If you find past mistakes, amending before the IRS contacts you is usually the cheapest fix.
This article is general information, not tax or legal advice; consult a qualified tax professional about your situation.
Crypto is volatile and risky; this is education, not financial advice. Do your own research.
