Starting with 2026 returns, exchanges report sales on Form 1099-DA, but they don't know what you paid for coins that came back from your own wallet. Cold Basis rebuilds the real cost basis across your exchanges and wallets in minutes.
Join early accessWatch-only: never asks for keys or seed phrases. Runs locally.
| Lot | Bought | Path | Basis |
|---|---|---|---|
| 0.40 BTC | Mar 2021 | Coinbase → Sparrow → Kraken | $22,900 |
| 0.25 BTC | Jun 2022 | Kraken → multisig → Kraken | $5,100 |
| 0.10 BTC | Nov 2024 | Strike → Sparrow → Kraken | $9,200 |
From 2026, exchanges file 1099-DA. Coins you deposit from your own wallet show up with missing or $0 basis.
Tools like Koinly work, until a consolidation or self-transfer gets booked as a sale and you spend a weekend fixing it by hand.
If you can't prove basis, the IRS assumes the worst. The gap can be tens of thousands of dollars of reported gain.
Add exchange CSVs and wallet xpubs (Sparrow, Unchained, Ledger). No keys, ever.
Self-transfers and consolidations are matched automatically, and each coin's original purchase is traced.
Get Form 8949, a clean import for your tax software, and an audit trail for your CPA.
No. Cold Basis is watch-only and uses public xpubs and exchange CSV exports.
Keep it. Cold Basis fixes the self-custody transfers they mis-match and hands back a clean import.
No. It produces records and forms for you or your CPA to file.
Early access opens January 2027 for the 2026 filing season. Join to be first.