A wallet is how you hold crypto. Custodial wallets (exchanges, brokers) hold keys for you and often produce CSV/API exports for tax software. Self-custody wallets (hardware/software) put you in control of keys; tax history comes from on-chain data and your own records.
Moving between your own wallets is often not a taxable disposal; moving to someone else usually is. Platform reporting (DAC8/CARF) focuses heavily on custodial providers.
Why it matters: incomplete wallet coverage is the #1 cause of broken crypto tax reports.
Educational definition — not tax advice. Rules vary by country.
