Crypto Cost Basis: The Records to Fix Before January
Most of the attention on crypto taxes goes to the question of whether a transaction is taxable. That part is fairly settled: the IRS treats digital assets as property, so selling, trading one coin for another, or spending crypto on goods and services can all trigger a capital gain or loss.
The part that actually consumes time and money is quieter. It is proving what you paid — your cost basis. And unlike the taxable-event question, basis is a records problem, which means it gets harder every month you leave it alone and nearly impossible once an exchange you used has shut down or purged your history.
The gain is easy. The basis is the hard part.
A capital gain is the difference between what you sold for and your adjusted basis. Exchanges are generally good at reporting the first number and frequently unable to supply the second.
That gap appears whenever assets have moved. An exchange knows what a coin sold for on its platform. It often does not know what you originally paid, because you bought it somewhere else and transferred it in. When basis cannot be substantiated, the conservative fallback is a basis of zero — and a basis of zero means the entire proceeds are taxed as gain.
We have seen reconstructions where the real economic gain was modest and the reported gain, on the records available, was several times larger. The tax difference was not a rules problem. It was a documentation problem.
Moving coins between your own wallets breaks the trail
The single most common way people destroy their own audit trail is entirely innocent: moving their own coins between their own wallets and exchanges.
A transfer between wallets you control is not a taxable event. But to an exchange’s reporting system it can look like a disposal on one side and an acquisition with unknown history on the other. Do that across three exchanges and two hardware wallets over four years and the chain of basis becomes genuinely difficult to rebuild.
Other events that complicate basis in ways people rarely record at the time:
- Staking and mining rewards — generally income when received, which then establishes basis going forward
- Airdrops and hard forks — receipt can create income and a new basis
- Paying transaction and gas fees in crypto — itself a disposal of the coin used
- Using crypto to buy something — a sale, whether or not it felt like one
What to capture while the year is still open
Almost everything that makes crypto reporting painful in April is cheap to prevent in the year the activity happens. While the year is still open:
- Export transaction history from every platform, now — not next spring. Exchanges close, get acquired, and limit how far back you can download.
- Keep a running log of transfers between your own wallets, with dates, amounts and both addresses. This is the record that makes a reconstruction possible later.
- Record income events when they happen — staking, mining and airdrop receipts, with the fair market value on the date received.
- Pick a basis method and stay with it. Consistency matters more than which defensible method you choose.
- Keep the wallet addresses themselves. A public address is often the only durable link between an exchange record and your own holdings.
None of this requires special software, though software helps. It requires the exports to exist before they can no longer be obtained.
If your records are already behind, that is fixable
Every situation is a little different. A short conversation will tell you whether any of this actually affects you — and exactly what to do about it if it does.
