Sixteen Years of Bitcoin: Resolved and Unresolved Issues in the Taxation of Crypto Assets

Bitcoin’s sixteenth anniversary in 2025 provides an important juncture to reflect on how tax law has responded to the emergence of crypto assets. Initially hailed as ‘the monetary experiment of our time’, Bitcoin and its successors have challenged fundamental tax concepts and exposed divergences in domestic and international tax systems. This article first revisits the debate on whether crypto assets should be characterized as ‘money’, demonstrating that classification matters only to the extent that tax consequences diverge across regimes. It then examines four unresolved issues that continue to occupy scholars and policymakers: the characterization of mining rewards as entrepreneurial income or windfall gains; the treatment of staking rewards as active or passive income; the tax consequences of blockchain hard forks; and the classification of collateral use of crypto assets in decentralized finance. Each issue reveals tensions between traditional tax analogies and the novel features of blockchain-based activities, highlighting trade-offs between theoretical purity and administrability. While global convergence is unlikely due to foundational differences in tax systems, the analysis underscores the importance of clarity, consistency, and functional approaches to ensure that taxation keeps pace with technological innovation.