What to Do When Your 1099-DA Shows $0 Cost Basis
Quick Answer
If your 1099-DA shows $0 cost basis, don't panic. This is fixable. It happens because your broker didn't have your cost basis data, especially for crypto you transferred in from an external wallet. You have every right to report your actual cost basis on your tax return. If you don't correct it, the IRS could tax you on the full sale proceeds instead of just your actual gain. Here's exactly what to do.
Why Does My 1099-DA Show $0 Cost Basis?
Many people received their first 1099-DA forms in early 2026 only to discover the cost basis box was blank or showed $0. This is incredibly common, and there's a good reason why.
For tax year 2025 (the first full year of 1099-DA reporting), most brokers are reporting gross proceeds but not cost basis. The IRS didn't require cost basis until 2026. Even then, brokers face a challenge: they often don't have cost basis information for crypto that was transferred in from external wallets.
Here's a typical scenario: You bought Bitcoin in 2020 through a peer-to-peer transaction or on an older exchange. You held it in a self-custodied wallet for five years. Then in 2025, you transferred it to Coinbase and sold it. Coinbase knows when and for how much you sold it (the proceeds). But Coinbase doesn't know that you bought it for $5,000 back in 2020. To them, it just appeared one day as an incoming transfer.
This is why so many 1099-DAs show $0 cost basis. It's not an error on your part. It's a limitation of how brokers track information.
Is This a Problem? (Yes, But It's Fixable)
If you leave your 1099-DA as-is with $0 cost basis, yes, this becomes a serious problem.
Here's why: The IRS also receives a copy of your 1099-DA from your broker. They'll expect to see that same transaction on your Schedule D. If your 1099-DA shows $40,000 in proceeds and $0 cost basis, the IRS will initially assume you have a $40,000 capital gain.
But that's wrong. If you actually paid $20,000 for the crypto, your real gain is only $20,000, not $40,000. You could end up paying taxes on gains you never actually made.
The good news: you have the right to report your actual cost basis, not the $0 on the 1099-DA. This is explicitly allowed by IRS rules. You simply need to show your work and keep documentation.
How to Find Your Actual Cost Basis
Finding your cost basis requires looking back at your transaction history. Here are the places to check:
1. Your broker's transaction history. Log into the exchange where you bought the crypto. Most major exchanges (Coinbase, Kraken, Gemini) let you download your full transaction history as a CSV file. This will show the purchase date, amount, and price you paid.
2. Your email and receipts. Many exchanges send confirmation emails when you buy crypto. Search your email for purchase confirmations. They usually include the amount and price paid.
3. Your bank or credit card statements. If you bought crypto with a debit or credit card, your bank or card statement will show the transaction date and amount. This doesn't directly give you the cost basis, but it narrows down the purchase window.
4. Wallet history. If you know the blockchain address where you received the crypto, you can use block explorers (like Etherscan for Ethereum or Blockchain.com for Bitcoin) to see when the transaction occurred. The date helps you track down purchase records.
5. Earlier tax returns. If you reported crypto transactions in prior years, check your previous Schedule D filings. You may have already documented the cost basis.
6. Crypto tax software. If you used crypto tax software in prior years to file your taxes, that software should have records of your historical transactions and cost basis.
How to Report Correct Cost Basis on Your Tax Return
Once you've found your actual cost basis, here's how to report it:
You do not copy the $0 cost basis from the 1099-DA onto your Schedule D. Instead, you report your actual cost basis on Schedule D and Form 8949 (Sales of Capital Assets).
Here's the key: Form 8949 has a line to indicate whether cost basis is being reported as shown on the 1099 or if you're using a different cost basis. You'll mark the box that says your cost basis is different.
Then, in the cost basis column on Form 8949, you enter your actual cost basis, not the $0 from the 1099-DA.
The IRS understands that 1099-DAs may not have complete cost basis data, especially in this transition year. By clearly showing your actual cost basis and documenting how you obtained it, you're providing the IRS with the correct information.
If the IRS matches your 1099-DA against your return later and notices a discrepancy, having documentation of your actual cost basis will protect you during an audit.
Using Crypto Tax Software to Fix Cost Basis Issues
The easiest way to handle $0 cost basis issues is to use crypto tax software.
FastCryptoTax is specifically designed to handle these scenarios. When you connect your exchange, FastCryptoTax imports all your transactions, including the 1099-DA data your broker submitted. If cost basis is missing, you can manually enter it, or FastCryptoTax can help you locate it.
The software then generates a correct Schedule D and Form 8949 that shows your actual cost basis, not the $0. It also flags discrepancies between what your broker reported and what you're actually reporting, so you understand exactly where and why there's a difference.
This takes a potential tax headache and reduces it to a few minutes of data entry and verification.
What If You Lost Your Purchase Records?
Some people genuinely can't find their original purchase records. Maybe it was years ago, or the exchange went out of business.
If you absolutely cannot locate your cost basis, you have options:
1. Use a reasonable estimate. You can estimate your cost basis based on the price of crypto at the time. If you know approximately when you bought the crypto, look up the historical price on CoinMarketCap or similar sources. This isn't perfect, but it's better than $0.
2. Use the closing price method. Some people use the price at market close on the day they received the crypto as a proxy for cost. This isn't ideal, but it's defensible.
3. Report $0 and disclose the issue. If you truly cannot find any records, you can report $0 cost basis but attach a detailed explanation to your return noting that you have no records. This shows good-faith effort.
In any case, if you're unsure, consult a CPA. They can help you navigate the IRS's rules on reconstructing basis and can advise on whether to file an amended return if you later find records.