Jim Cramer says he will sell all Bitcoin, citing a three- to four-year quantum risk

Jim Cramer said he plans to sell all of his Bitcoin after warning that quantum computing could threaten the cryptocurrency within the next three to four years, echoing remarks from IBM chief executive Arvind Krishna, who told him investors should get "rather paranoid" about the risk on that timeline. Parts of the crypto community treated Cramer's latest bearish turn as an "inverse Cramer" buy signal. The warning comes as debate over crypto's long-term cryptographic security has intensified. Krishna told CNBC's Mad Money that investors should think in terms of three to four years for the risk to become serious, while Google researchers wrote in a March paper that future quantum computers may be able to break some of the cryptography protecting Bitcoin and other digital assets with fewer resources than previously thought. The paper, whose coauthors included Justin Drake of the Ethereum Foundation and Dan Boneh of Stanford, urged vulnerable crypto communities to begin migrating to post-quantum protections without delay, though it did not say Bitcoin's cryptography can be broken today. Recent research cited in the new report suggested almost 7 million Bitcoin, worth nearly $500 billion, could be exposed if quantum computers eventually become capable of breaking wallet digital signatures. Krishna also said quantum computing could begin contributing measurably to IBM's revenue and profit in 2028 or 2029 and become a trillion-dollar source of value by the end of the 2030s. Earlier market context remains mixed, with Bitcoin previously trading above $63,500 but still down 27% for the year, while whale wallet transfers and weak spot volumes had pointed to softer liquidity. The quantum threat timeline remains disputed, with Blockstream CEO Adam Back arguing the risk is at least 20 to 40 years away, Bernstein giving Bitcoin three to five years to prepare for a quantum-resistant security upgrade, and Bitget Wallet analyst Lacie Zhang saying practical attacks remain unlikely within the next decade.