The European Banking Authority, European Securities and Markets Authority and European Insurance and Occupational Pensions Authority warned that advanced quantum computers could undermine cryptography securing transactions, communications, databases and blockchains before the technology has a viable commercial application. In their Autumn 2026 risk update, the European Supervisory Authorities urged supervisors and market participants to prepare now while continuing to monitor emerging-technology risks. Quantum computing could improve financial processes, fraud and compliance monitoring, and pricing, but the regulators said its security risks could materialize first. Bitcoin’s exposure stems from its public-key cryptography, which a sufficiently capable fault-tolerant quantum computer could theoretically attack to derive private keys from exposed public keys. Coinbase’s Independent Advisory Board estimated that roughly 7 million BTC could eventually face quantum-related risks, including about 5 million BTC linked to address reuse and some large exchange cold wallets. The warning comes as the Ethereum Foundation targets 2029 for making Ethereum’s Layer 1 quantum-resistant and StarkWare reports completing the first quantum-safe Bitcoin transaction on mainnet. The broader EU risk update also identified dependence on information and communication technology providers outside the European Economic Area, private credit and increasingly capable artificial intelligence models as vulnerabilities, while saying the EU financial system remains resilient. EU member states adopted a post-quantum migration roadmap in June 2025, with migration beginning by the end of 2026 and high-risk systems and critical infrastructure completing the transition by 2030.