What to do if you forgot to report your taxable crypto trades on last year's return
Leaving crypto trades off an old return is common, and it is fixable. Here is how the IRS spots the gap, how far back it can look, and how to correct a past return before it turns into a notice.
A missed crypto trade on a past return is one of the most common things people bring to a crypto-tax pro. It usually isn't fraud. You didn't get a tax form from the exchange, you didn't know a coin-for-coin swap counted, or the records got scattered across three or four platforms and one year slipped through. The fix is an amended return, and your position is stronger the sooner you file it.
What has changed is how easy it now is for the IRS to see the gap. A few years ago, unreported crypto often stayed invisible because exchanges sent nothing to the government. That gap is closing.
Why the IRS is more likely to notice now
Starting with the 2025 tax year, custodial exchanges and other digital-asset brokers report your sales to the IRS on Form 1099-DA. The IRS gets its own copy. When the proceeds on that form don't line up with what your return shows, the matching system flags it, the same way an unreported stock sale or W-2 would flag. Cost-basis reporting is phasing in after gross proceeds, so early notices often overstate the tax because the IRS sees the full sale amount and none of what you paid.
Two other things make silence riskier than it used to be. The digital-asset question sits at the top of Form 1040, and answering "no" in a year you had taxable activity is a misstatement you signed. Separately, the IRS has used John Doe summonses to pull user records from major exchanges. Being on a platform that never mailed you a form does not mean your data is out of reach, and a public blockchain lets investigators tie wallet addresses back to real identities.
How far back the IRS can look
The audit window is not open forever, but it is longer than most people assume, and it depends on how much was left off.
The takeaway is practical: a trade you forgot in 2021 or 2022 can still be within reach, and the way you close it out is your choice for now, not the IRS's.
The pros who fix underreported crypto for a living know how to file a clean amendment and rebuild missing basis. We'll match you with one.
Get matched with a pro who handles it →The like-kind myth that still causes trouble
A lot of the underreporting traces back to one wrong idea: that swapping one coin for another was a tax-free like-kind exchange under Section 1031. It was not. The IRS treats a coin-for-coin trade as a sale of the first coin followed by a purchase of the second, both measured at fair market value on the day of the swap. Since 2018, Section 1031 has applied only to real property, and the IRS has said crypto never qualified even before that change. Every swap is a taxable event whether or not any cash reached your bank account.
The same logic catches things people rarely think of as sales. Spending crypto on goods or services is a disposal. Converting a coin to a stablecoin is a disposal. If the value moved from one asset to another, that is a moment the IRS expects to see reported.
What amending actually involves
You correct a past year by filing Form 1040-X for that year, with a revised Schedule D and Form 8949 that include the trades you missed. Each year that was wrong gets its own 1040-X.
The work that matters is basis. For every disposal, you need what you originally paid, so the amended return reports gain or loss rather than the full sale price. If your basis records are thin, reconstruct them from exchange exports and wallet history instead of estimating, because a number you can't support is a number you may have to defend later.
Filing before the IRS contacts you is the point. If the correction produces a balance due, expect interest from the original due date and possibly an accuracy penalty of 20 percent on the underpayment. Coming forward on your own generally puts you in a better spot on penalties than answering a notice after the fact. If the correction runs in your favor, you usually have three years from the original filing date, or two years from when you paid, to claim the refund.
What to pull together before you file
- Each exchange's complete transaction export for every year involved, not just the year-end summary.
- Wallet and on-chain history for transfers, swaps, staking, and any DeFi activity.
- Records of anything you bought with crypto, since spending it is a disposal.
- Your original return for each year, so the 1040-X shows the change clearly.
What to do this week
- Pin down the wrong years. Missed trades, a "no" on the digital-asset question, or a coin swap you treated as tax-free.
- Gather records first. A rushed 1040-X with wrong basis creates a second problem on top of the first.
- Amend, don't ignore. The worst outcomes come from silence after the IRS already has your exchange data.
- Get help if the years are tangled. Several exchanges, DeFi, staking, or missing basis is exactly when a specialist earns the fee.
A forgotten trade is a paperwork problem, not a crime, as long as you fix it. Correcting it on your own terms is almost always cheaper and calmer than explaining it later in response to a letter.