Citibank: Quantum Computing Poses Greater Risk to Bitcoin Than Ethereum, ~One-Third of BTC Exposed

According to a Citibank report covered by CoinDesk on May 18, quantum computing breakthroughs are accelerating faster than expected, compressing the timeline for security threats to crypto assets. The bank identified Bitcoin as facing the highest quantum exposure due to more conservative governance and slower protocol upgrades. Specifically, early P2PK addresses and wallets with publicly exposed keys are vulnerable to quantum attacks. Citibank estimates approximately 65,000-69,000 BTC (roughly one-third of circulating supply) face quantum risk. The report noted that Ethereum and other proof-of-stake networks can upgrade more frequently and may have greater flexibility in migrating to quantum-resistant cryptography.