Missing crypto cost basis: rebuild the record trail.

An unknown value is a question to investigate

When a crypto report shows missing cost basis, begin with the asset's acquisition history. Gather the original purchase or receipt records, identify the relevant accounts, and follow later movements to the disposition being reviewed.

The IRS explains that basis depends on how the digital asset was acquired. For a purchase, the U.S. dollar cost is generally the starting point, but other acquisitions and transaction costs can require different analysis. A missing import does not establish zero basis.

1. Find where the history starts to break

Identify the sale or disposition with an unknown value, then look backwards through the receiving account and any earlier wallet or exchange. Note whether the history begins with a deposit rather than an acquisition.

Check whether the import excluded earlier years, used the wrong date range, or omitted an account. Keep those possibilities as questions until the available evidence supports a conclusion.

• Asset and quantity being reviewed
• Disposition date and source transaction reference
• Receiving account and earlier source accounts
• Available acquisition records and their date coverage
• Any transfer or import gap that remains unexplained

2. Gather evidence of the original acquisition

Useful evidence may include a trade confirmation, original exchange export, purchase statement, or records of another type of receipt. A payment record can support a review, but the payment must be connected to the relevant asset and units.

Keep the date, quantity, U.S. dollar values, and available fee information together. Do not substitute today's price for a missing acquisition value or treat the date of a later deposit as proof of the original purchase date.

3. Connect transfers to the acquisition

Compare the sending and receiving records using the asset, dates, quantities, and transaction references. Explain any difference that needs review, rather than assuming two similar entries are the same movement.

A blockchain transaction can help show movement between addresses. It does not, by itself, prove what you paid on an exchange or establish every fact needed for basis. Keep the acquisition evidence with the transfer trail.

4. Separate purchases from other receipts

Flag assets received as a gift, inheritance, reward, payment, or another type of receipt. Do not automatically apply a purchase-price explanation to every acquisition.

If several lots of an asset were acquired, the identification of the units disposed of also matters. The applicable rules, wallet or account history, and tax year need professional review. This guide does not select a lot-identification method for your return.

5. Keep unsupported values unresolved

Create a reconstruction note that names each source, explains the connections you found, and identifies missing evidence. Keep originals and working corrections separately so the result can be followed.

If the records remain incomplete, discuss the available evidence and the reporting question with your tax professional. There is no promise that every missing purchase can be recovered, and an unexplained gap should not be hidden by an invented value.

Ask for help with the specific gap

An initial inquiry can name the tax year, the asset, the platforms involved, and where the report first shows missing basis. Mention which original records are still available.

Nancy can discuss whether a consultation, records review, or preparation engagement fits the situation. Agree the scope before sending detailed financial files.

Common questions