Self-custody record guide

MetaMask cost basis: reconstruct transfers, swaps and bridges

MetaMask is a wallet interface, not a complete tax ledger. Build the trail from on-chain activity and original acquisition evidence.

Direct answer: MetaMask does not create a complete acquisition-cost history merely because a token appears in the wallet. To reconstruct the record, list every relevant wallet address, locate the original acquisition, follow transaction hashes through transfers, swaps and bridges, and connect the final deposit or disposal to the broker record.

Why a wallet trail is different

A centralized exchange can provide account-level trades and statements. A self-custody wallet may expose public transactions without explaining why each transaction occurred, who controlled the other address or how an imported token should be classified. You must add context.

Build a wallet inventory first

MetaMask and a hardware wallet may expose the same address. Do not duplicate transactions merely because the same account was accessed through different interfaces.

Transaction reconstruction table

EventEvidenceContext to add
Exchange withdrawalExchange record and on-chain hashWhich controlled wallet received it?
Wallet-to-wallet moveMatching send and receiptDid you control both addresses?
SwapToken out, token in, gas and protocolWhat transaction type does current guidance require?
BridgeSource burn/lock and destination receiptIs the same economic asset continuing?
Exchange depositWallet send and exchange receiptDoes it connect to a later disposal?

Five-step reconstruction

  1. Locate the first acquisition of the asset or predecessor asset.
  2. Record date, quantity, price, fees and source.
  3. Trace each transfer with the public transaction hash.
  4. Document swaps, bridges, liquidity activity and gas separately.
  5. Connect the asset trail to the final broker deposit and reported disposal.

Common causes of software differences

When software may be appropriate

Manual review may be practical for a few transfers. Reconciliation software may be appropriate for many addresses, chains, swaps, bridges or smart contracts. Software still requires review of unmatched transfers and transaction classifications.

Koinly is an affiliate option for complex wallet histories. We may earn a commission; it does not replace qualified advice.

Start with a complete inventory

The free checklist includes wallet addresses, transaction hashes, exchange exports and missing-basis warnings.

Get the free checklist

Sources and limits

See MetaMask Support for current wallet and activity instructions and the IRS digital-assets guidance for federal information. This independent guide is not affiliated with MetaMask and is not tax advice.