If the cost basis field on your 1099-DA is blank, it is likely not a mistake by the exchange. It usually means the asset is a "noncovered asset." Simply put, the IRS currently only requires exchanges to report cost basis for assets bought and held on the same platform after January 1, 2026. For coins you transferred in from outside, the platform does not have your original purchase records, so the cost basis remains empty.
This blank cost basis most commonly appears in the following three transfer scenarios:
Check if your transferred asset falls into a "noncovered" category
Case A: Assets transferred from another exchange or a self-custody wallet
Whether you moved funds from Binance to Coinbase or from MetaMask to Kraken, any asset not directly bought with cash or stablecoins on that platform is considered a noncovered asset. Platforms like Gemini clearly label such assets and warn that the cost basis is blank. When you sell, the exchange only reports the total proceeds to the IRS. You must fill in the cost part yourself.
Case B: "Old assets" bought in 2025 or earlier
The IRS rules are phased in. In 2025, exchanges only need to report total proceeds. Mandatory cost basis reporting starts in 2026. So, if you bought coins in 2025 or earlier and kept them on the same exchange, when you sell in 2026, the system typically sees no traceable cost information for that batch and leaves it blank by default.
Case C: Assets received through staking, mining, or airdrops
Staking rewards, mining outputs, and airdropped tokens are treated as income, not purchases. The platform has no "purchase price" for you, so the cost basis is blank. You need to use the fair market value (FMV) at the time you received them as the cost basis for that batch of coins—not report the cost as "0."
Risks of a blank cost basis when you self-check
Common mistake: Many people see a large proceeds number on the 1099-DA and think that is the tax they owe. In reality, that is your gross proceeds without deducting costs. If you do not fill in the correct cost basis on your tax return, the IRS automated matching system will assume your cost is 0 and calculate tax on the full proceeds.
Risk reminder: Once the IRS issues a CP2000 notice (automated underreporter notice), explaining your cost basis afterwards is very difficult and time-consuming. If you receive two duplicate 1099-DA forms or a form with a cost basis of 0, first determine whether it is a noncovered asset situation described above. If it is, you do not need the exchange to correct the form. Instead, report the actual cost on your own Form 8949 and Schedule D, and keep the original purchase records as proof.
Prepare original records to trace your cost basis
Since the platform does not report the cost, these numbers must be filled in from your own history.
How to do it:
Find the original purchase records: If you bought from another exchange, export the 2025 or earlier trade history CSV from that platform. If you bought via a wallet (e.g., a DEX swap), find the swap transaction hash on a block explorer like Etherscan and record the price and quantity at that time.
Choose your cost basis method: Starting in 2026, the IRS requires FIFO (first-in, first-out) as the default cost basis method; however, for 2025 transactions you can still use methods like HIFO or LIFO. Whichever you choose, stay consistent in your tax software, or the numbers may not match the 1099-DA.
Use exchange tax tools to fill in gaps: Kraken's Tax Center lets you manually add missing cost basis. Coinbase's Tax Center will flag noncovered assets, but you can correct them in your tax software yourself—no need for the platform to reissue the 1099-DA.
Completion standard: You can produce a complete transaction record (Excel sheet or a tax software report) where every sale matches a purchase date and cost, and the total matches the proceeds on the 1099-DA.
How to verify when you're done
When you get your 1099-DA, check two things: First, the "Proceeds" total must match the sale revenue you calculated yourself. Second, if the "Cost Basis" is blank or says "Noncovered," simply ignore it and enter your cost into Form 8949 using your own records.
Next step: Before filing this year, export and archive the 2025 trade CSVs from all major platforms (Binance, OKX, Coinbase, Kraken, etc.). The IRS gave a transition period, but record-keeping requirements get stricter from 2026 onward. Make a habit of noting the original purchase price every time you transfer assets in—it's far easier than digging through six months of records later.
