Short answer: for most 2025 transactions, a blank cost basis field on Form 1099-DA is not an error. Custodial brokers were required to report only gross proceeds for dispositions effected on or after January 1, 2025; basis reporting was deferred. A blank field means the broker did not report a figure — it does not mean your basis is zero, and it does not relieve you of the obligation to compute gain or loss yourself. The correct next step is to verify which tax year the form covers, confirm whether the asset is treated as covered or noncovered, and reconstruct cost basis from your own records before you file.
This crypto tax guide explains how to read the form, what documentation to assemble, and how to build a reconciliation you can defend if the IRS matches your return against the copy it already holds.
Missing basis vs. zero basis: the distinction that matters
These are two different tax positions, and conflating them is the single most expensive mistake taxpayers make with this form.
- Missing (blank) basis means the broker did not furnish the number. The taxpayer supplies it on Form 8949 and Schedule D. Nothing about the underlying economics has changed. This is what most people mean when they encounter 1099-DA missing cost basis.
- Zero basis is a substantive assertion that you acquired the asset at no cost — a genuine outcome for certain airdrops, forks, or mining and staking rewards only where the corresponding income was not previously recognized. Where reward income was recognized, the amount included in income generally becomes your basis in the asset.
Reporting a blank field as zero inflates your taxable gain, sometimes dramatically. Reporting a fabricated basis exposes you to accuracy-related penalties. Neither shortcut is acceptable; the reconstruction described below is.
Why the cost basis field is blank
Understanding the mechanism tells you whether you are looking at a policy artifact or a genuine defect.
1. The statutory phase-in
The 2024 final broker regulations phase reporting in over two years. Brokers must report gross proceeds for transactions effected on or after January 1, 2025, and must report basis on certain transactions effected on or after January 1, 2026. The IRS has stated plainly that most statements will not provide the basis of the taxpayer’s digital asset transactions for the 2025 tax year, and that basis must be calculated by taxpayers before the 2025 return can be filed. The first forms carrying mandatory basis data cover 2026 dispositions and arrive in early 2027.
2. Covered vs. noncovered status
Even after the phase-in, basis reporting is limited. Mandatory basis reporting applies only to “covered securities” — digital assets acquired on or after January 1, 2026 and held continuously in the broker’s account. Any asset acquired before that date, or transferred into a broker’s platform, is a noncovered security for which the broker is not required to report basis. If you moved coins in from a self-custody wallet or another exchange, expect the 1099-DA cost basis blank box to stay empty for years.
3. The broker never had the acquisition history
Custodial brokers can only report what passed through their own books. Assets acquired peer-to-peer, mined, received as payment, bridged, or held on a platform that has since wound down leave no acquisition record on the reporting broker’s system.
4. Voluntary reporting creates inconsistency
Some brokers populated basis for 2025 even though they were not obliged to. A figure you did not expect is not automatically correct — a voluntarily furnished basis may exclude fees, ignore transfers in, or apply a lot-selection method that differs from the one you actually use.
What to check on the form you received
Work through the document methodically before touching your records.
| Check | Why it matters |
|---|---|
| Tax year | Determines whether basis reporting was mandatory. 2025 forms: proceeds only. 2026 forms onward: basis for covered assets. |
| “CORRECTED” box | A corrected form supersedes the original. Reconcile to the latest version only. |
| Payer identity and TIN | Confirms which platform filed and which account the activity belongs to. |
| Recipient TIN | A mismatch is a defect to raise with the broker immediately — it drives IRS matching. |
| Gross proceeds | Your reconciliation anchor. This is the figure the IRS holds. |
| Noncovered indicator | For 2025 it will be checked on nearly every form. Confirms basis is yours to compute. |
| Asset identifier, quantity, dates | Lets you tie each reported disposition to a specific lot in your own ledger. |
| Sale of a first-issuance asset | The IRS has issued FAQ guidance on placement of certain proceeds; check for duplicate reporting of the same amount in more than one box. |
| Number of forms received | One per broker. Multiple platforms mean multiple forms and multiple reconciliations. |
Also note what is absent: decentralized finance brokers and some foreign brokers are not required to file Form 1099-DA or furnish a statement, and taxpayers must report all taxable digital asset activity whether or not a statement was received.
Records to gather
Assemble these before attempting any calculation. The quality of your reconstruction is entirely a function of the quality of this file.
- Complete transaction exports (CSV) from every exchange you have ever used, including closed accounts. Request archived data early; retrieval can take weeks.
- Purchase confirmations and fiat rails: bank transfers, card statements, wire confirmations tying dollars to acquisitions.
- On-chain transfer history for every self-custody address, with transaction hashes. Transfers between your own wallets are not dispositions, but they carry basis with them and must be traced.
- Fee records: trading commissions, network fees, and other acquisition costs that are capitalized into basis.
- Income documentation for staking rewards, mining, airdrops, and crypto received as compensation, with the fair market value recognized at receipt.
- Prior-year returns, Forms 8949, and any carryforward positions.
- Allocation records under the wallet-by-wallet transition. The universal-pooling approach is no longer available; unused basis had to be allocated across accounts and wallets under the safe harbor in Rev. Proc. 2024-28. Locate that allocation — it is now the starting point for lot identification.
How to reconcile
- Build a master ledger. Merge every export into one chronological record, normalized to consistent asset tickers, timestamps in a single time zone, and USD values.
- De-duplicate transfers. Match outgoing and incoming movements between your own wallets so a single relocation is not counted as a sale and a purchase.
- Reconstruct lots. For each unit disposed of, identify the acquisition event, date, and cost, including capitalized fees.
- Apply a consistent identification method on an account-by-account basis, consistent with your Rev. Proc. 2024-28 allocation. Document the method; do not switch between assets or accounts opportunistically.
- Tie proceeds to the form. Your reported proceeds for that broker should agree to the 1099-DA total. Investigate every variance — timing differences, wash of transfer activity, or duplicated boxes are common causes.
- Document estimates. Where a record genuinely cannot be recovered, use a defensible, contemporaneous valuation source and preserve a written explanation of the methodology and its limits.
- Report on Form 8949 and Schedule D, using the appropriate box for how to report crypto without cost basis, and carry adjustments through consistently.
No crypto tax software and no service can restore a basis history that was never recorded. Reconstruction is evidentiary work, not a lookup.
Worked example (illustrative; assumptions stated)
Assumptions: U.S. individual taxpayer; 2025 tax year; assets held as a capital asset; no wash-sale or constructive-sale issues; figures rounded.
- March 2023: purchases 2 ETH on Exchange A for $3,400, plus a $20 trading fee. Basis: $3,420.
- August 2024: transfers both units to a self-custody wallet. Network fee paid in ETH is a separate disposition; ignored here for clarity. Not a taxable sale of the 2 ETH.
- January 2025: transfers the 2 ETH into Exchange B.
- September 2025: sells 2 ETH on Exchange B for $7,600 gross.
Exchange B issues a 1099-DA showing $7,600 in proceeds. The basis field is blank and the noncovered indicator is checked, because the units were acquired elsewhere and transferred in. The taxpayer reports proceeds of $7,600, basis of $3,420, and a long-term capital gain of $4,180 on Form 8949 — supported by the Exchange A confirmation, the on-chain transfer hashes, and the Exchange B trade record. Treating the blank field as zero basis would have overstated the gain by $3,420.
When to contact the broker, and when to contact a professional
Contact the broker where the form itself is defective: wrong taxpayer identification, proceeds that do not match your trade history, a transaction that is not yours, duplicated amounts, or a voluntarily reported basis you can show is wrong. Ask for a corrected form in writing and keep the correspondence.
Contact a qualified tax professional where the form is accurate but your history is incomplete: multi-year records spanning defunct platforms, substantial DeFi or bridging activity, business or mining operations, prior returns that may need amending, or an IRS notice already in hand. A broker cannot fix an incomplete acquisition history — only reconstruction and, where appropriate, professional judgment can.
FAQ
Can I ignore Form 1099-DA if the basis is blank?
No. The IRS receives an identical copy and matches reported proceeds against your return. An unreported or unreconciled figure is a common trigger for automated notices.
Does a blank field mean my basis is zero?
No. It means the broker did not report a figure. Zero basis is a substantive position that applies only in narrow circumstances and should never be adopted by default. Missing cost basis is a reporting gap, not a valuation.
What if the reported basis is present but wrong?
Request a corrected form. If the broker declines or cannot correct it in time, report the correct figures with an appropriate adjustment on Form 8949 and retain full documentation of the discrepancy.
I received no form at all. Am I in the clear?
No. DeFi and certain foreign platforms are outside the reporting regime, and the obligation to report taxable dispositions is independent of whether a statement was issued.
I already filed and then found the correct basis. What now?
Amended returns are the usual route where the correction is material. Assess the effect on tax due before deciding, and act promptly if a notice has been issued.
When will brokers actually report basis?
For covered assets acquired on or after January 1, 2026 and held continuously with the broker. Those forms arrive in early 2027. Noncovered assets will continue to show blank digital asset cost basis indefinitely.
Primary sources
- IRS, Final regulations and related IRS guidance for reporting by brokers on sales and exchanges of digital assets (T.D. 10000)
- IRS Fact Sheet FS-2025-06, digital asset proceeds reporting
- Instructions for Form 1099-DA and Form 8949 for the applicable tax year
- Rev. Proc. 2024-28 (basis allocation safe harbor)
Always confirm the instructions for the specific tax year on the form before filing; rules in this area are phasing in and change annually.
This guide is general information, not tax advice, and does not address any specific taxpayer’s circumstances.
Need help understanding your crypto tax documents? Contact HolderTax.
