In this guide
→ The Rule Changed More Than Most Traders Realize→ FIFO: The Default You Get Without Doing Anything→ Specific Identification: What It Actually Requires→ The Wallet-by-Wallet Rule Changes the Underlying Math→ What Happens When Your Records Disagree With the Broker's 1099-DA→ A Worked Example Showing Why the Method Actually Matters→ The Practical Approach for 2026→ A Note on International Filers Reading This From Outside the US
At a glance
| Feature | FIFO | Specific Identification |
|---|---|---|
| IRS status | Automatic default | Allowed only if lot documented at the trade |
| Documentation | None required | Must identify exact lot at or before the sale |
| Rising-market gain | Larger, often long-term rate | Can pick higher-cost lot, smaller gain, often short-term |
| Timing | Applies automatically | Must elect before or at the trade, not after |
| Best for | Long-term holders wanting simplicity | Active traders who document lots in real time |
The Rule Changed More Than Most Traders Realize
For years, crypto investors treated cost basis method selection, FIFO, LIFO, or HIFO, as a relatively free choice made at tax time to minimize the current year’s gain. That framing is now out of date. Under current IRS rules, only two methods are actually permitted for digital asset dispositions: FIFO as the automatic default, and Specific Identification, defined narrowly under the applicable Treasury regulation. What this means in practice is that HIFO and LIFO are not independently valid methods anymore; they survive only to the extent that a specific disposal genuinely qualifies as Specific Identification under the statute, meaning you identified and documented the exact lot being sold at or before the time of the transaction, not after the fact when preparing your return.
FIFO: The Default You Get Without Doing Anything
First In, First Out assumes that whenever you dispose of an asset, you are selling the oldest lot you still hold of that asset first. If you bought Bitcoin in three separate purchases over two years and then sold a partial amount, FIFO treats that sale as coming from your earliest purchase, using that lot’s original cost basis to calculate the gain or loss. FIFO is the method applied automatically if you have not made a valid, properly documented Specific Identification election for a given disposal.
In a rising market, FIFO tends to produce larger reported gains, because your oldest lots typically have the lowest cost basis relative to a current, higher sale price. This is not necessarily a bad outcome, older lots also tend to qualify for long-term capital gains treatment, which is taxed at a meaningfully lower rate than short-term gains, so FIFO’s tendency to realize your oldest holdings first often shifts gains into the lower long-term rate bracket even as the dollar amount of the gain itself looks larger.
Specific Identification: What It Actually Requires
Specific Identification lets you choose which particular lot you are disposing of, rather than being forced into the oldest-first FIFO order. The requirement that trips people up is timing and documentation: the identification has to happen at or before the transaction, through a genuine, contemporaneous record, not reconstructed months later when you sit down to file and realize picking a different lot would produce a better tax outcome. A broker or exchange that lets you tag a specific lot at the moment of sale, and retains that record, supports a valid Specific Identification election. Deciding after the fact which lot you wish you had sold does not.
What people commonly call HIFO, Highest In, First Out, selling your highest cost basis lot first to minimize the current year’s taxable gain, is not a separate legal method in its own right anymore. It is only valid to the extent that a specific, documented Specific Identification election happens to select the highest cost basis lot for a given disposal. The label “HIFO” describes a strategy or a pattern of choices; the actual legal basis for making that choice has to be genuine Specific Identification, done correctly and on time.
The Wallet-by-Wallet Rule Changes the Underlying Math
Starting with the 2025 tax year, taxpayers are required to track cost basis on a wallet-by-wallet and account-by-account basis rather than pooling all holdings of the same asset across every exchange, wallet, and cold storage device into one universal pool, which was the common practice for years before this rule took effect. This is a structural change, not just a preference: if you hold Bitcoin across three exchanges and two hardware wallets, each of those five locations now maintains its own separate cost basis history, and a disposal from one wallet can only draw on that specific wallet’s own lots, not the cheapest lot you happen to hold somewhere else entirely.
The practical effect is that a trader who moved assets frequently between wallets and exchanges over the years, without careful tracking of which specific lots went where, may find that reconstructing an accurate wallet-by-wallet history is now the harder and more consequential task, more so than deciding which cost basis method to apply once the lots are properly assigned to the correct wallet.
What Happens When Your Records Disagree With the Broker’s 1099-DA
Form 1099-DA, now issued by custodial brokers for digital asset dispositions, reports the transaction using the broker’s own default method, generally FIFO, unless you have made a valid election directly with that specific broker. If you have been tracking your own cost basis using a documented Specific Identification approach that differs from what the broker reports on your 1099-DA, the lot pools diverge, and reconciling the two becomes an annual task rather than a one-time adjustment. The mechanism for this reconciliation is Form 8949: report the proceeds figure exactly as shown on the 1099-DA, enter your own correctly documented basis in the basis column, and use adjustment code B to flag that the reported basis differs from your own records.
Temporary relief extended through the end of 2026 allows taxpayers to continue using their own cost basis method and lot identification on their own books even where it differs from a broker’s default reporting. That relief is explicitly temporary; the expectation going into 2027 is that taxpayers will need to either match their own method to the broker’s default or establish their chosen method directly with the broker rather than reconciling the difference after the fact every year.
A Worked Example Showing Why the Method Actually Matters
Consider an investor who bought one Bitcoin at 20,000 dollars two years ago, another at 60,000 dollars a year ago, and a third at 45,000 dollars six months ago, all in the same wallet. Selling one Bitcoin today at a current price of 65,000 dollars produces a very different taxable outcome depending on which lot is treated as sold. Under FIFO, the sale draws from the oldest lot, the 20,000 dollar purchase, producing a 45,000 dollar gain, but one that qualifies for long-term capital gains treatment since it was held over a year. Under a validly documented Specific Identification election naming the 60,000 dollar lot, the same sale produces only a 5,000 dollar gain, but as a short-term gain taxed at ordinary income rates since that lot was held under a year. Running both scenarios before executing a sale, rather than after, is the only way to actually know which outcome is better for your specific tax situation, and Specific Identification only protects the more favorable outcome if the lot was named before or at the moment of the trade, not reconstructed afterward once you see which answer you would have preferred.
The Practical Approach for 2026
Given the relief window closing at the end of 2026, the single most valuable action for anyone with meaningful crypto holdings across multiple wallets is establishing a clean, wallet-by-wallet lot record now, using software that supports proper Specific Identification documentation at the time of each disposal rather than reconstructing it later, and confirming directly with each broker or exchange whether they support setting a Specific Identification method going forward rather than defaulting you into FIFO automatically on every trade.
For traders who have historically relied on informally calling their approach HIFO without genuinely contemporaneous, per-wallet lot documentation, 2026 is the year to close that gap, because the transition relief that has been tolerating looser record-keeping is a temporary window, not a permanent accommodation.
A Note on International Filers Reading This From Outside the US
The FIFO-versus-Specific-Identification framework described here is specific to US federal tax treatment under IRS rules; other jurisdictions apply meaningfully different cost basis rules that should not be assumed to mirror the US approach. The UK, for instance, applies a same-day and 30-day matching rule followed by a pooled average cost basis method for remaining holdings, structurally different from either FIFO or Specific Identification as defined under US rules. Canada generally requires an adjusted cost base, averaging cost across identical holdings rather than allowing lot-level selection at all in most circumstances. Anyone filing crypto taxes outside the US should confirm their own jurisdiction’s specific cost basis methodology directly rather than assuming any of the US-specific rules described here apply to their own filing obligation.
For anyone who splits time across multiple countries, or holds crypto assets while being tax resident in more than one jurisdiction during a given year, this distinction is not a minor technicality; using the wrong jurisdiction’s cost basis methodology can produce a materially incorrect reported gain or loss figure, and consulting a tax professional familiar with the specific combination of jurisdictions involved is worth the cost before relying on any single-country framework applied to a cross-border situation.
The Bottom Line
FIFO remains the simple, default-by-inaction method, while anything resembling HIFO or LIFO only holds up as genuine, documented Specific Identification made at the time of each transaction. Combined with the wallet-by-wallet basis rule now in effect, the accounting discipline required to legally minimize crypto tax through lot selection has increased meaningfully, and the temporary relief allowing looser reconciliation with broker 1099-DA reporting expires at the end of 2026.
Marko Jambrek
Licensed architect in Zagreb, 30 years of practice (Vastu + sustainable design). Writes about AI tools through a lens of order and long-term value, tests before recommending.
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