Moving Bitcoin into self-custody and later returning it to an exchange can break mandatory cost-basis reporting, even if ownership never changes. For 2026 US tax forms, brokers may still report the sale proceeds while leaving the acquisition cost blank, putting the recordkeeping burden back on the investor. https://cryptoslate.com/bitcoin-self-custody-creates-a-massive-cost-basis-blind-spot-on-your-2026-crypto-tax-forms/