BasisBridge — 1099-DA cost-basis reconciliation
Your 1099-DA shows what you sold. It doesn’t show what you paid.
BasisBridge reconciles every disposal on your 1099-DA against your purchase records — FIFO lot matching, transfer-in tracing, a missing-basis exception list with the evidence for each fix — and delivers a Form 8949-ready workbook your CPA can file from. Flat price. No API keys to hand over. No software to learn.
Basis-gap estimator
How much proceeds are sitting on a blank basis?
Count the sales on your 1099-DA where the basis box is blank, and their average proceeds. That is the population the reconciliation engine rebuilds — FIFO lot matching, per account.
Sales with no basis reported on the form.
Gross proceeds, as printed on the 1099-DA.
Records reconciliation only — not tax advice or filing. Basis figures we cannot evidence are flagged as exceptions, never invented.
The problem
Basis was left to the holder
Your 1099-DA shows what you sold. It doesn't show what you paid.
2025 forms reported proceeds only
Form 1099-DA reporting began with 2025 transactions, when brokers reported gross proceeds only — cost basis was left to the holder.
2026 basis covers covered lots only
For 2026, basis appears only for covered lots — everything bought earlier or transferred in stays noncovered, basis blank.
Transferred-in coins arrive basis-blind
Transferred-in coins arrive basis-blind at every broker — permanently.
The IRS matches the proceeds figure
The IRS matches the proceeds figure it received. An unreconciled return is a notice waiting to happen.
How it works
Three steps to a 8949-ready pack
Send your files
Send your exchange CSV exports + your 1099-DA totals (secure intake list provided after checkout — never send passwords or API keys).
We run the reconciliation
We run the reconciliation engine + a human exception review: every blank-basis sale FIFO-reconstructed, every mismatch and transfer-in flagged with its evidence.
You get the pack in 5 business days
You get the pack in 5 business days: 8949-ready workbook, exception list, evidence index, and a one-page CPA handoff memo.
A note on method: FIFO by default, per account, documented in the pack. If your records support a different lot method you’ve consistently used, note it at intake — that alternative-method path is handled as the SOP’s manual lot-order process and labeled in the pack; the engine itself runs FIFO.
The workbook, as a ledger
Every row a span that ties out
| Acquired | Sold | Asset | Proceeds | Basis | Gain / loss | Term |
|---|---|---|---|---|---|---|
| 2024-01-10 | 2025-03-01 | BTC | 45,000.00 | 20,000.00 | 25,000.00 | long |
| 2025-06-01 | 2025-07-01 | ETH | 6,000.00 | 4,100.00 | 1,900.00 | short |
| 2025-06-01 | 2025-09-01 | ETH | 3,000.00 | 2,000.00 | 1,000.00 | short |
| — | 2025-08-01 | SOL | 1,000.00 | — | — | — |
The SOL row is an exception, not a figure: lots short, basis left blank and flagged INSUFFICIENT_LOTS — never zero-based. Records reconciliation only — not tax advice or filing.
The pack
The deliverable, typeset as a ledger
Records reconciliation only — not tax advice, not a tax return.
Pricing
Flat prices, published up front
Pay once or monthly — no calls, no quotes, no hourly billing.
Reconcile
$149
one-time
- Up to 500 disposals
- 1 tax year
- FIFO reconstruction + variance check + 8949-ready workbook
Most popular
Reconcile + Evidence
$349
one-time
- Up to 2,500 disposals
- Full evidence index
- Transfer-in tracing
- CPA handoff memo
- Priority turnaround
CPA Desk
$79
/mo
- Rolling reconciliation desk for CPA/tax firms
- Client packs monthly
- Exception queue managed for you
The Tie-Out Promise
If our proceeds total doesn't tie to your 1099-DA total, we keep working until the variance is explained line-by-line or you get a full refund. Basis figures we cannot evidence are flagged as exceptions, never invented.
Honest scope
Records reconciliation only. Never tax advice, never filing.
Records reconciliation only. We are not a CPA firm, we give no tax advice, and we never file your return. We reconcile records and index evidence. Filing decisions stay with you and your tax professional.
Do you file my return?
No. Records reconciliation only; we are not a CPA firm and give no tax advice.
What method?
FIFO by default, per account, documented in the pack. If your records support a different lot method you've consistently used, note it at intake and we reconcile on that basis and label it.
What about DeFi / self-custody sales with no 1099-DA?
Include the wallet exports; disposals with no broker form are reconciled and listed separately so nothing is silently dropped.
Objections, answered
Keep your tracker. We finish the reconciliation.
“I already have Koinly/CoinTracker.”
Keep it for tracking. When its exception queue is the part you dread, we finish the reconciliation and evidence it.
“My CPA can do this.”
They can — at hourly rates, from the same messy CSVs. We hand them a pack they can file from in minutes.
“Is this tax advice?”
No — deliberately. We reconcile records and index evidence. Filing decisions stay with you and your tax professional.
What’s in every pack
Disposal-by-disposal proceeds ↔ basis ↔ gain/loss, short/long term split · 1099-DA total variance check (our proceeds total vs. the form's, to the dollar) · Missing-basis exception list — nothing silently zero-based · Transfer-in tracing notes (transfer date is never used as acquisition date) · Evidence index: every basis figure points at its source record
Your 1099-DA shows what you sold. Rebuild what you paid.
Flat price. No API keys to hand over. No software to learn. The pack in 5 business days — proceeds tied to your 1099-DA total, to the dollar, or the variance explained.