CRYPTO TAX · IRS COMPLIANCE · DISPUTE
Davit Cho — Crypto Tax Researcher · CEO at JejuPanaTek (2012–) · Patent Holder #10-1998821 · Founder of LegalMoneyTalk
Published: April 30, 2026 · 13 min read · 100% Independent · Ad-Free
CRYPTO TAX · IRS COMPLIANCE
Your 1099-DA arrived. The numbers don't match your records. You have 72 hours before this becomes harder.
The IRS already received the same form. Their automated reconciliation engine already compared the broker's numbers against any return you've filed. If you do nothing, the broker's numbers become the default truth — and you spend the next 18 months explaining why your version is right. If you act in the next three days, the dispute becomes paperwork. After that, it becomes a defense.
π BOTTOM LINE — IN 60 SECONDS
- Don't ignore the form. The IRS got an identical copy and already cross-checked it.
- 4 mismatch types exist: wrong basis, wrong proceeds, missing transfers, duplicate reporting. Each has a different fix.
- 72-hour window is real. Verify in 24h, document in 48h, dispute or file with adjustment in 72h.
- Form 8949 has codes for this. Code B for basis, Code T for transfers, Code O for other — and you must use them, not just override numbers silently.
- Your goal is a paper trail, not perfection. A documented good-faith dispute is bulletproof. An undocumented "I just put the right numbers" is audit bait.
A 1099-DA That Doesn't Match Is Not a Mistake to Erase — It's a Negotiation You Just Entered
Most crypto holders, when they see a 1099-DA with the wrong cost basis or wrong proceeds, react in one of two ways. Either they panic and pay tax on the broker's number even though it's wrong. Or they ignore the broker's number entirely and quietly file Schedule D with their own correct figures, hoping nobody notices the gap.
Both reactions lose. The first overpays. The second creates a reconciliation flag that the IRS examiner system will catch automatically — because the broker filed the same form with the IRS, and the matching engine runs every return against every 1099-DA it received.
The correct frame: a mismatched 1099-DA is the start of a documented dispute. The IRS does not expect every broker form to be perfect. They expect taxpayers to either accept it, dispute it, or file an adjustment that's clearly explained on Form 8949. The third path is the one that wins — and it has rules.
The Four Types of 1099-DA Mismatches (And Why Each Needs a Different Fix)
Type 1 — Wrong Cost Basis
The broker reports a cost basis lower (or sometimes higher) than your actual basis. This is the most common mismatch in 2026 because brokers don't have your full transfer history — they only know what was deposited into their platform, not what you originally paid for it elsewhere. Fix: File Form 8949 with Column (e) showing the broker's reported basis, Column (g) showing your adjustment, and Code B in Column (f). Your dispute paper trail is the chain of records proving your real basis (purchase invoice, original exchange CSV, on-chain transfer hash).
Type 2 — Wrong Proceeds
The broker reports gross proceeds higher than what you actually received. Common cause: the broker's price feed used a different reference price than the actual execution price, or fees weren't netted properly. Fix: File Form 8949 with the broker's proceeds in Column (d), your adjustment in Column (g), and Code O in Column (f). Attach a statement explaining the proceeds discrepancy and reference your trade confirmation showing the actual execution price.
Type 3 — Missing Transfer Information
You transferred crypto into the broker from a self-custody wallet or another exchange. The broker had no idea where it came from, so they reported a basis of zero — or worse, they used the deposit-day market price as the basis. Fix: File Form 8949 with Code T in Column (f) and your real basis in Column (g). Provide the original acquisition record (the wallet, exchange, or transaction that established your original basis) along with the on-chain transfer evidence linking the two.
Type 4 — Duplicate Reporting
Two brokers reported the same disposition. Most common case: you transferred crypto between exchanges and one of them treated the outbound transfer as a sale. Or a broker double-reported because of an internal accounting reset. Fix: Identify the duplicate, file Form 8949 reporting the genuine transaction once, and attach a statement identifying the duplicate 1099-DA and explaining why it was a non-taxable transfer rather than a disposition. Keep both 1099-DAs in your audit file.
Critical rule:
For every mismatch, the broker's reported number goes on Form 8949 first. Your correct number does not replace it. Your correct number appears as an adjustment in Column (g) with the appropriate code in Column (f). This is the difference between "documented dispute" and "silent override" — and the IRS reconciliation engine treats them as completely different events.
The 72-Hour Response Timeline
Hour 0–24: Verify the Mismatch Exists
Pull the actual 1099-DA from the broker's tax center (don't rely on a forwarded email screenshot). Open your own per-lot ledger. Compare every transaction line by line — date, asset, units, basis, proceeds. Note every discrepancy. Most "mismatches" turn out to be one of three things: (a) genuine broker error, (b) a different lot-selection method between you and the broker, or (c) a transfer the broker treated incorrectly. Identifying which one matters because the fix differs.
Hour 24–48: Document the Source of Truth
For every disputed line, gather the underlying records that prove your version: original exchange CSV showing the purchase, on-chain transaction hash for the transfer, trade confirmation showing the execution price, wallet snapshot at the relevant date. Save them in a single timestamped folder. The folder is your defense — not the spreadsheet you build from it. Examiners ask for sources, not summaries.
Hour 48–72: Decide — Dispute With the Broker or Adjust on Form 8949
If the deadline allows and the error is clearly the broker's (e.g., wrong proceeds price), submit a written correction request to the broker's tax department asking for a corrected 1099-DA. Most major brokers (Coinbase, Kraken, Gemini) have a formal correction process. If the broker won't issue a correction, or if the deadline is tight, proceed to file your return with Form 8949 adjustments using the appropriate codes. Both paths are legitimate. The path you don't take is "silently file with my numbers and hope."
Beyond 72 Hours: Why Speed Matters
Once you file the return, your dispute path narrows. Pre-filing, you can request a corrected 1099-DA. Post-filing, you're in amendment territory (Form 1040-X) which is more visible to examiners and harder to win quickly. The 72-hour window is not a legal deadline — it's the practical window where you still have all the dispute paths available before filing forces you into a single one.
Form 8949 Adjustment Codes: B, T, O — Use Them Correctly or Trigger an Audit
Form 8949 Column (f) accepts a one- or two-letter code that tells the IRS examiner what kind of adjustment you're making. The codes most relevant to crypto 1099-DA disputes are these three.
Code B — Basis Reported Incorrectly
Use Code B when the broker's reported cost basis (Column e) is wrong and you are correcting it via Column (g). This is the workhorse code for crypto disputes because basis errors dominate the mismatch landscape. The IRS examiner sees Code B and knows: "the taxpayer agrees with the proceeds but disputes the basis." That's a routine adjustment, not a red flag — provided your supporting records are clean.
Code T — Form 1099-DA Reports Incorrect Type or Information
Use Code T when the form misclassifies the transaction — most commonly when an inbound transfer was reported as if it were a purchase, or an outbound transfer was reported as if it were a sale. Code T is the proper signal for "this isn't actually a taxable event the way the broker reported it." Pair it with a clear adjustment statement so the examiner doesn't have to guess what was reclassified.
Code O — Other Adjustments (Including Proceeds Errors)
Code O is the catch-all when neither B nor T fits — typically used for proceeds discrepancies, fee netting issues, or wash-sale-adjacent fact patterns specific to crypto. Code O carries slightly more examiner attention than B because it's less common, so always attach a written statement explaining what was adjusted and why. Without the statement, Code O looks ambiguous and invites a follow-up letter.
The unbreakable rule:
Never silently override broker numbers without a code. Filing Schedule D with "your" basis when a 1099-DA shows a different basis, with no Code B and no adjustment, is the exact pattern that triggers the IRS automated mismatch letter (CP2000). The mismatch letter is recoverable, but it costs you 6–12 months and a documentation back-and-forth that the Code B path avoids entirely.
The Audit Defense File: Six Folders That End the Dispute
If you do every other step right but lose the documentation, you lose the dispute. If you keep clean documentation, every other step becomes survivable — even if you make a small error somewhere. The audit defense file is the single most important deliverable in the whole process. Six folders, organized in this order:
- Folder 1 — Broker 1099-DA. The original PDF or downloaded file from the broker's tax center. Keep the unedited version exactly as received.
- Folder 2 — My Ledger. Your per-wallet, per-lot ledger reflecting your actual basis and proceeds for the disputed transactions.
- Folder 3 — Source CSVs. The original transaction exports from every relevant exchange and wallet. Raw, unmodified files.
- Folder 4 — Dispute Letter. If you submitted a correction request to the broker, the request and any reply.
- Folder 5 — Corrected 1099-DA. If the broker issued a correction, the corrected form (and proof of the original).
- Folder 6 — Form 8949 Worksheets. The line-by-line worksheet showing how each adjustment was calculated, with code, amount, and source reference.
When the IRS sends a CP2000 mismatch letter (and they will, for any unflagged adjustment), you respond by referencing this folder structure. Most CP2000s are resolved with a single-page reply when the file is clean. Without the file, the same letter becomes a months-long discovery process where you reconstruct what should have been documented at the time.
BOTTOM LINE
A mismatched 1099-DA is not a problem to hide. It's a process to document.
The IRS expects errors. They don't expect cover-ups. The taxpayers who lose are the ones who silently file with their own numbers, hoping the mismatch doesn't trigger anything. The taxpayers who win are the ones who treat the mismatch as a documented dispute from minute one — verify the numbers, gather the records, file Form 8949 with the right code, and keep the six-folder file ready. The win isn't perfection. It's the paper trail.
Quick FAQ
Q: Can I just file Schedule D with my correct numbers and ignore the broker's 1099-DA?
No. The IRS receives the same 1099-DA the broker sent you, and their automated reconciliation engine compares it against your Schedule D. A silent mismatch generates a CP2000 letter automatically. Filing the broker's number on Form 8949 with a Code B (or T or O) adjustment is the documented path that avoids the letter.
Q: How do I request a corrected 1099-DA from a broker like Coinbase or Kraken?
Each major broker has a tax-specific support channel. Submit a written correction request that identifies the specific transaction (date, asset, units), states the broker's reported value, your value, and the source records that support your version. Keep a copy of the request and any reply. If the broker refuses or doesn't respond before your filing deadline, proceed with Form 8949 adjustment instead.
Q: What if the basis is missing entirely on the 1099-DA because I transferred crypto in?
This is Type 3 (Missing Transfer Information). Use Code T on Form 8949 and supply your real basis in Column (g) using your acquisition records — original exchange CSV, on-chain transaction hash showing the original purchase, or wallet record. Code T tells the IRS the broker didn't have visibility into the transfer, which is a legitimate, common situation in 2026.
Q: What's the penalty if I don't dispute and just pay tax on the broker's wrong number?
No legal penalty — but you've voluntarily overpaid tax on phantom gains. You can file an amended return (Form 1040-X) within three years to claim the refund. The dispute process is far cleaner before filing than after.
Q: Can the IRS audit me purely because of a 1099-DA mismatch?
The first response is not an audit — it's a CP2000 mismatch notice, which is automated. A CP2000 is resolvable through written reply with documentation in the vast majority of cases. An actual audit is a separate, escalated process that's rare unless the documentation reply is missing or contradictory. This is precisely why the six-folder defense file matters.
Related Reading
| Per-Wallet Cost Basis Migration | Powell FOMC & Tax Window | About Davit Cho |
Official IRS Resources
• Form 8949 instructions (adjustment codes)
• Form 1099-DA instructions
• Understanding your CP2000 notice
• IRS Digital Assets hub
Editorial perspective by Davit Cho. LegalMoneyTalk is an independent ad-free research publication. This article is for educational purposes and reflects general analysis of IRS guidance and Form 8949 instructions as of April 2026. It does not constitute tax, legal, or investment advice. Consult a crypto-specialized CPA or tax attorney for your specific situation.
