Reviewed November 8, 2026.
The short version
A blank cost-basis field on Form 1099-DA does not automatically mean your tax return is wrong. The form reports a broker's information; your return reports the tax result using that information and your records. First identify the transaction year, whether the broker was required to report basis, and how the return already treated the sale.
The IRS taxpayer guidance says to calculate basis before filing and report taxable digital-asset transactions whether or not you receive the form. Basis is generally your tax investment in the units disposed of. Proceeds are what the disposition produced. They are different amounts.
The reporting transition matters
The 2026 Form 1099-DA instructions distinguish covered and noncovered digital assets. Covered status generally depends on acquisition after 2025 in the broker's custodial account under the specified conditions. A transfer into a broker does not, by itself, make an older asset covered.
| Transaction year | Basis-reporting point | Source |
|---|---|---|
| 2025 | The initial broker-reporting year generally supplies proceeds; do not assume basis appears | IRS taxpayer guidance; IRS transaction FAQs |
| 2026 and later | Basis reporting is required for covered digital assets; noncovered basis reporting can be voluntary | 2026 instructions, General Instructions |
| Any affected year | Your gain or loss still depends on supported basis and the applicable reporting rules | IRS taxpayer guidance |
These are reporting rules, not a tax exemption for noncovered assets. The instructions contain transaction-specific exceptions and optional methods; the table is not a claim that every transfer generates a form.
Check three records side by side
Use the broker statement, your transaction-level records and the filed return. Match asset, date, units and proceeds. Then trace acquisitions and transfers supporting the basis used. Separate an empty field from an affirmative zero and from an incorrect amount. Ask the broker what the field means before treating those situations as equivalent.
For example, suppose a sale has $12,000 of proceeds and a supported $8,000 basis. Ignoring fees solely for this illustration, the gain is $4,000. If the filed return already used those amounts correctly, a later statement with a blank basis field does not alone establish an amendment need. If the return instead used zero basis because records were missing, the comparison raises a correction issue. This is invented arithmetic, not a client result or an IRS safe harbor.
Broker corrections and return corrections are separate
If the form is wrong, request a correction from the issuer and retain the original, corrected form and correspondence. The IRS says it cannot correct the broker's form and that taxpayers should not wait to file. That does not excuse an inaccurate return or remove a filing deadline. Resolve the reporting treatment with the records available and consider an extension when appropriate under the applicable filing rules.
For 2026 transactions, also check whether an identification method valid under Notice 2026-20 produces a result different from the broker statement. The notice addresses that possibility. A mismatch is a reason to reconcile the evidence, not automatically replace your supported records with the broker's calculation.
Before amending, identify the actual return error, affected year and supporting adjustment. Basis reconstruction, an amendment and responding to an IRS notice are distinct tasks. A CP2000 notice has its own response instructions; sending an amended return is not a substitute for reading them.
For related guidance, read cost-basis correction and amended returns.
For related guidance, read multi-wallet records.
Discuss your situation
For a scoped engagement inquiry, email Noah Green with a short description of the issue and any upcoming deadline. Do not send tax returns, identifying numbers, wallet keys or other sensitive records through ordinary email. Secure document instructions follow separately. Payment and your signature may initiate an engagement request; they do not mean the case has been accepted. I review the facts after payment and must countersign the engagement letter and accept the case before work begins. The accepted written engagement governs scope. Contacting me does not extend an IRS deadline.
This article provides general federal tax information, not advice for your specific facts. State and international rules may differ. No outcome is guaranteed. There is no guarantee of any specific outcome.
Sources
- IRS: 2026 Form 1099-DA instructions
- IRS: Understanding Form 1099-DA
- IRS: Digital-asset transaction FAQs
- IRS Notice 2026-20
Prepared by Noah Green, CPA, CFE.