A blank basis field is not proof of zero cost
Form 1099-DA is a broker reporting document. A missing cost basis field does not establish that the asset cost nothing. Review the reporting year, the broker's coverage, and the evidence of acquisition before deciding how the transaction belongs on your return.
The 2026 IRS instructions distinguish a blank field from an actual zero basis. When a broker is not reporting basis for a noncovered digital asset, the instructions tell the broker to leave the field blank. Zero is entered only when the asset actually had a basis of zero.
1. Check the transaction year
The broker reporting phase-in starts with gross proceeds for transactions occurring in 2025. Basis reporting is required for certain transactions occurring from 2026. Most 2025 statements, received in 2026, did not include basis.
The transaction year and the year you receive the document are different. For a 2026 statement, check whether the asset is covered and what the broker actually reported. Do not assume all assets on all statements have the same basis reporting treatment.
2. Compare the sale with the source history
Check the broker name, asset, quantity, sale date, and proceeds against the relevant transaction records. Keep the original statement and any corrected copy so the preparer can see which document is current.
If a software total differs, compare the same accounts and periods before concluding that either number is wrong. A report that includes other exchanges is not the same dataset as a statement from one broker.
3. Follow the acquisition behind missing basis
A receiving platform may have a deposit and a later sale but not the earlier purchase on another exchange. Find the original acquisition documents and the transfer history connecting that acquisition to the sold asset.
A broker statement may be incomplete for basis purposes even when the sale proceeds are present. Keep the sale information and the acquisition question separate.
4. Record the coverage and each unresolved difference
List activity outside the statement's coverage, including other platforms and relevant wallet history. Create a short discrepancy note identifying the statement line, the source record, the difference, and the evidence still needed.
If you believe the statement itself is incorrect, ask the issuer about its correction process and retain the correspondence. Review the return reporting question with your tax professional; do not silently overwrite source documents.
- Original Form 1099-DA and any corrected statement
- Export for the same broker and transaction period
- Purchase or other acquisition documentation
- Transfer references connecting the relevant accounts
- A list of mismatches and activity outside the broker statement
When a consultation can help
Ask for an individual review when the statement and your source records do not line up, acquisition information is missing, or you are unsure which history the software report includes. The relevant tax year and transaction facts matter.
Nancy can discuss a defined consultation or a tax preparation engagement. Start with the broker, year, and issue; agree the scope and document-sharing method before sending financial files.
Common questions
Does missing cost basis mean the whole sale is profit?
A missing field alone does not establish your gain. The acquisition evidence and the applicable reporting rules need to be reviewed.
Why can a software report differ from Form 1099-DA?
The sources and periods may differ, and imported acquisition or transfer history may be incomplete. Compare the records behind each report before drawing a conclusion.
What if I never received Form 1099-DA?
The absence of a broker statement does not by itself remove a reporting obligation. Review your activity and the applicable return requirements with your tax professional.
Primary sources
- IRS: Instructions for Form 1099-DA (2026), including Box 1g
- IRS: Digital assets — broker reporting phase-in
- IRS: Digital asset reminders for the 2025 tax year
This guide explains records and general reporting questions. Your tax year and circumstances need an individual review before advice or return preparation.