Nearly 30% of Bitcoin Supply Faces Quantum Risk, Glassnode Finds
Glassnode research estimates 6.04 million BTC, about 30.2% of issued supply, has already exposed public keys and could be targetable by a future quantum computer. Exchange-held coins and address reuse account for a large share of the operational exposure.
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What the Glassnode Data Shows
Glassnode estimates that 6.04 million BTC, or 30.2% of issued supply, has had its public key exposed on-chain and would be vulnerable if a sufficiently powerful quantum computer became available, according to research published Wednesday. Decrypt values that balance at more than $469 billion at the time of writing. NewsBTC, citing the same analysis as relayed by crypto trader Evans on X, rounds the figure to nearly 30% of supply. The two reports agree on the headline number, though Decrypt notes that some earlier estimates have run closer to 7 million BTC.
Structural Versus Operational Exposure
Glassnode divides the exposed supply into two groups. Structural exposure totals 1.92 million BTC, or 9.6% of supply, and covers coins held in script formats that reveal public keys by design, including early pay-to-public-key outputs, legacy multisignature structures and some Taproot outputs. Many of these coins may be effectively immovable.
The larger group is operational exposure, at 4.12 million BTC, or 20.6% of supply. Those coins were not inherently vulnerable but became so through address reuse, since a public key is broadcast when a spend occurs and any remaining balance at that address is left exposed. NewsBTC gives the same 4.12 million BTC figure for this category.
Exchange Exposure Varies Widely
Centralized exchanges account for 1.66 million BTC within the operationally unsafe bucket, about 8.3% of total supply and roughly 40% of operationally unsafe coins. NewsBTC cites exchanges holding more than 1.6 million BTC in potentially exposed addresses, consistent with that figure. Decrypt reports that exposure differs sharply by platform: Coinbase's labeled balances are only 5% exposed, while Binance's are 85% and Bitfinex's 100%. Glassnode cautioned that the data reflects custody design rather than a risk ranking or solvency signal for any firm.
Market Backdrop and Protocol Debate
NewsBTC places the findings alongside a sharp fall in trading activity, citing CryptoQuant contributor Darkfost's estimate that Bitcoin spot volume has dropped about 81% since October 2025, with Binance down from $198.6 billion to $36.4 billion over the same period. Darkfost reads the lull as a possible late-stage correction signal, a view the outlet presents as interpretation rather than established fact. Decrypt frames the quantum findings within the developer debate over BIP-360, a proposed set of quantum-resistant transaction formats, and a separate proposal that would freeze coins not migrated by a set deadline. Decrypt also notes that Q-Day estimates range from 2030 to 2032 and later. Glassnode itself does not predict when or whether a cryptographically relevant quantum computer will arrive.
Why It Matters
For Traders
Exchange-linked exposure and reserve handling may draw closer scrutiny, but Glassnode stresses the data does not signal near-term risk for any specific platform.
For Investors
Roughly 30% of supply sitting in exposed keys makes a long-horizon quantum migration path, including BIP-360, a material question for Bitcoin's security model.
For Builders
Address reuse is the main controllable driver of operational exposure, so wallet and custody tooling that enforces fresh addresses reduces risk now.
This article is for information only and is not financial advice. Read the full disclaimer.
