The filing must be made in the Assets and Rights section, under Group 08 – Crypto Assets, using the following codes: 81: Bitcoin (BTC) 82: Other cryptocurrencies (Altcoins) 83: Stablecoins 88: Non-fungible tokens (NFTs) 89: Other tokens Filing means informing the Federal Revenue Service about the possession of these assets as of December 31, regardless of whether they were sold during the year.Capital Gains Taxation Simply holding crypto assets does not incur in taxation.