How to Document Stolen Cryptocurrency for a Tax Loss Claim

12 October 2026

If your cryptocurrency was stolen in a scam, you can claim a capital loss on your taxes, but only if you properly document the theft according to your tax authority’s rules. The loss is treated like a theft of any other asset: you report it as a capital loss, which can offset capital gains or, in some cases, reduce ordinary income. The key steps are establishing the date of theft, proving your cost basis, and showing that the loss is complete and uncollectible.

Confirm the Loss Is Recognizable for Tax Purposes

Tax authorities generally allow a theft loss deduction only when the loss is actually sustained and not reasonably recoverable. This means you cannot claim the loss while there is still a realistic chance of getting the funds back - for example, if law enforcement has frozen the scammer’s wallet or if a civil lawsuit is pending. You must wait until the theft is considered final. In practice, this often means the date the scammer moved the funds beyond your reach, such as through a mixer or to an exchange where you have no legal claim.

Gather your transaction records

You need a clear chain of evidence linking your purchase of the stolen crypto to the theft. Collect:

• Exchange or wallet logs showing the outgoing transaction to the scammer’s address.
• Blockchain transaction IDs for the transfer, which you can verify on a block explorer.
• Proof of your cost basis: receipts, exchange trade history, or wallet records showing when and at what price you acquired the stolen crypto. If you bought it on an exchange, download the trade history CSV. If you mined it or received it as payment, document the fair market value at receipt.
• Proof of ownership: screenshots of your wallet interface showing the balance before and after the theft, plus the transaction history.

Document the theft incident itself

Tax authorities typically require a contemporaneous record of the theft. Create a written narrative that includes:

• The date and approximate time you discovered the theft.
• The method of theft (e.g., phishing link, seed phrase leak, smart contract exploit).
• The scammer’s wallet address (if known).
• Any communications with the scammer, such as emails or social media messages.
• A timeline of your actions after discovery (e.g., reporting to exchange, filing police report).

File a Police Report (Even If It Goes Nowhere)

Most tax authorities require a police report or a similar official complaint to substantiate a theft loss. The report does not need to lead to recovery - it simply establishes that the loss occurred and that you reported it. File the report with your local police department or your country’s cybercrime unit. Keep the case number, officer’s name, and a copy of the report. If the police refuse to take a report, get that refusal in writing.

Determine the loss amount

The loss amount is generally your cost basis in the stolen crypto - what you paid for it, not its value at the time of theft. For example, if you bought 1 BTC for $30,000, and it was worth $60,000 when stolen, your loss is $30,000 (the cost basis). If you acquired the crypto for free (e.g., airdrop, mining), your cost basis may be zero, meaning no deductible loss.

• If you held the stolen crypto for less than one year (short-term), the loss offsets short-term capital gains first.
• If you held it longer than one year (long-term), the loss offsets long-term gains.

If your total capital losses exceed your capital gains, you can typically deduct up to $3,000 (or equivalent in your jurisdiction) against ordinary income per year, with the remainder carried forward.

Report the Loss on Your Tax Return

The specific form varies by country:

• United States: Use Form 8949 to list the theft as a capital asset disposition. Report the date of theft (or the date you determined the loss was complete) as the sale date, and the cost basis as the cost. Enter the proceeds as zero. Attach a statement explaining the theft.
• United Kingdom: Report the loss on your Self Assessment tax return under “Capital gains summary - other disposals.” Describe the loss as “theft of cryptoassets.”
• Canada: Report on Schedule 3 (Capital Gains or Losses) with a note that the disposition was due to theft.

Check your tax authority’s current guidance, as rules for crypto theft losses have changed in some jurisdictions. In the U.S., for example, personal casualty and theft losses were limited to federally declared disasters after 2017, but crypto theft may still qualify as a capital loss if the crypto was held as an investment.

What cannot be done

• You cannot claim a loss for stolen crypto if you still control the private keys or have any access to the funds.
• You cannot claim a loss for crypto that was lost due to your own negligence (e.g., giving away your seed phrase voluntarily) unless the tax authority treats it as theft.
• You cannot claim a loss if you are actively pursuing recovery through a civil lawsuit and expect to recover the funds - wait until the outcome is clear.
• You cannot claim a loss for the value of the stolen crypto at the time of theft if that value exceeds your cost basis. Only the cost basis is deductible.

Keep All Records for at Least Seven Years

Tax authorities can audit theft loss claims years later. Maintain your documentation - transaction logs, police report, blockchain evidence, and your loss calculation - in a secure, organized file. If you later recover any portion of the stolen crypto, you may need to report that as income or adjust your prior loss claim.

Documenting a crypto theft for taxes is a precise, paperwork-heavy process, but it is one of the few financial remedies available after a scam. Treat it with the same care you would any other capital loss on your return.

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