A report featured in Bitcoin Magazine’s The Quantum Issue says 6,900,573 BTC were cryptographically exposed as of block 950,000, equal to 34.45% of circulating supply. The publication says that figure should not be read as the amount of bitcoin likely to be lost in a quantum event.
In the brief, exposure is defined as a cryptographic condition: the public key has already appeared on-chain. The authors say real-world risk depends on whether holders can respond, whether the entities involved are still operating, whether balances are large enough to justify attack costs, and how quickly funds can be moved. Once those factors are applied, the risk picture becomes narrower and more concentrated in dormant holdings.
How the exposed supply was broken down
The raw exposed total stands at 6,900,573 BTC, or 34.45% of supply, across 16,047,454 groups and 102,347,011 UTXOs. The migration estimate attached to that view is about 140.99 days.
An active exposed view with balances of at least 1 BTC and a five-year threshold contains 3,331,639 BTC. That equals 16.63% of supply and 48.28% of the raw exposed total, spread across 46,163 groups and 4,906,508 UTXOs, with an estimated migration time of about 9.37 days.
A separate view covering unspent and inactive balances of at least 1 BTC contains 3,413,767 BTC, or 17.04% of supply and 49.47% of the raw exposed total. That set includes 113,627 groups and 2,669,847 UTXOs, with an estimated migration time of about 5.29 days.
After excluding known entities while keeping coins attributed to Satoshi Nakamoto, the exposed amount falls to 2,277,978 BTC. That is 11.37% of supply and 33.01% of the raw exposed total, distributed across 73,658 groups and 1,096,018 UTXOs, with an estimated migration time of about 2.56 days.
Under the same filter, balances of at least 10 BTC still account for 2,187,481 BTC, or 10.92% of supply and 31.70% of the raw exposed total. That view contains 39,897 groups and 365,830 UTXOs, with a migration estimate of about 23.33 hours.
At 100 BTC or more, the target set shrinks to 351,654 BTC, or 1.76% of supply and 5.10% of the raw exposed total. Those coins are spread across just 675 groups and 33,573 UTXOs, with an estimated migration time of about 2.17 hours.
The report says those migration estimates are meant to compare relative scale, not to predict coordination difficulty, fee pressure, or user behavior in the real world.
Four main takeaways from the brief
The headline exposure number overstates theft risk
The authors say the raw figure of 6,900,573 BTC intentionally treats exposure as a cryptographic condition, meaning the public key is already visible on-chain. That is a valid starting point, they write, but it is not the same as economic loss risk. An exchange wallet still in operation, an institutional multisig setup, a dormant early address, and an abandoned private key can all be exposed in the same cryptographic sense while having very different odds of being moved.
Active and known entities look less alarming than the raw number suggests
The active-and-at-least-1-BTC filter covers 3,331,639 BTC, or 48.28% of all exposed supply. The report says that is a large amount of bitcoin, but it is concentrated in 46,163 groups rather than scattered across millions of unmanaged holders.
It identifies the largest visible cluster of active exposure as operating entities such as exchanges, brokerages, custodial multisig operators, stablecoin infrastructure, and mining-related wallets. According to the brief, those participants are the most likely to track quantum developments, coordinate wallet rotation, and complete migration before a practical attack window opens.
The report does not dismiss that exposure. It says the category still carries coordination and execution risk. But it draws a distinction between that and lost-key risk, adding that in a credible threat scenario, active custodial and exchange balances would usually be among the first coins to move.
The harder long-term problem is dormant exposure that cannot respond
Once active entities are removed and the view is narrowed to balances of at least 1 BTC that are either unspent or inactive, the exposed supply stands at 3,413,767 BTC. Excluding known operating entities while keeping Satoshi-linked coins reduces that figure to 2,277,978 BTC, spread across 73,658 groups and 1,096,018 UTXOs.
The brief describes those 2.28 million BTC as the cleanest approximation in the dataset for the harder-to-mitigate part of the exposed surface. It includes early holders, inactive self-custody, old address reuse, dormant P2PK outputs, and coins that may already be lost or otherwise unable to respond. The authors place the most stubborn part of practical quantum risk in that segment.
Attack economics narrow the target set even more
The report says a capable quantum attacker would still face operating costs, limited throughput, opportunity cost, transaction fees, and operational risk. For that reason, a rational target list is unlikely to include every exposed public key. Higher-value exposed balances would be the more likely focus.
That contraction shows up quickly once balance thresholds are applied. In the view that excludes known entities and counts only dormant or never-spent balances, the 10 BTC-and-up category still contains 2,187,481 BTC, but only 39,897 groups and 365,830 UTXOs remain. At 100 BTC and above, the set drops to 351,654 BTC across just 675 groups and 33,573 UTXOs.
Script-type observations across thresholds
This section of the report looks only at unspent and inactive balances while excluding known operating entities. Coins attributed to Satoshi are kept unless a balance threshold removes them.
- P2PK: 1,715,778 BTC at 1 BTC or more, 1,715,539 BTC at 10 BTC or more, and 10,246 BTC at 100 BTC or more. The brief says P2PK dominates dormant exposure at lower thresholds because early P2PK outputs are exposed by design and are mostly inactive.
- P2PKH: 408,789 BTC at 1 BTC or more, 356,368 BTC at 10 BTC or more, and 273,865 BTC at 100 BTC or more. The report says P2PKH becomes dominant in the 100 BTC-and-up view once Satoshi-era 50 BTC outputs are excluded.
- P2SH: 43,444 BTC at 1 BTC or more, 34,225 BTC at 10 BTC or more, and 21,113 BTC at 100 BTC or more. The brief says this category drops sharply after known operators are removed, leaving a relatively small amount of dormant script-hash exposure.
- P2WPKH: 8,696 BTC at 1 BTC or more, 5,271 BTC at 10 BTC or more, and 2,194 BTC at 100 BTC or more. The report says its share is very small in the dormant non-entity view, which matches more modern wallet behavior and activity patterns.
- P2WSH: 2,938 BTC at 1 BTC or more, 2,886 BTC at 10 BTC or more, and 2,750 BTC at 100 BTC or more. The brief says this category is very small after known entities are excluded, and that the much larger P2WSH exposure likely belongs to institutions that are still active.
- P2TR: 98,327 BTC at 1 BTC or more, 73,193 BTC at 10 BTC or more, and 41,486 BTC at 100 BTC or more. The report says Taproot outputs remain exposed at the key level, but the high-value, dormant, non-entity portion is still limited.
The brief adds that script-type totals may differ from headline metrics by a few BTC because the dashboard rounds values at the script-type level.
Why the ranking changes when the threshold rises
The report says the apparent shift from P2PK dominance at the 10 BTC threshold to P2PKH dominance at the 100 BTC threshold should not be read as P2PK risk disappearing.
It attributes the change to the filter itself. In this dataset, P2PK outputs attributed to Satoshi carry 50 BTC per public key, so they are included at 10 BTC and excluded once the public-key balance threshold moves above 50 BTC. That exclusion is what drives P2PK from about 1.716 million BTC in the 10 BTC-and-up view to about 10,000 BTC in the 100 BTC-and-up view.
The report’s conclusion
The strongest reading of the block 950,000 snapshot, according to the brief, is that bitcoin’s cryptographic exposure is large while its practical exposure is much narrower. Known active entities make up a large share of exposed supply, but they are also the participants most likely to migrate quickly.
The more persistent risk, the report says, sits with dormant, unresponsive, and possibly lost coins. Once known entities and lower-value targets are filtered out, the economically attractive target set becomes much smaller. At the 100 BTC threshold, only 675 groups remain, holding 351,654 BTC in total.
The data source is the Bitcoin Quantum Exposure Dashboard snapshot at block 950,000. The analysis also relies on a methodology PDF for the dashboard that was separately provided to editors. The article says the piece appears in the latest print edition of Bitcoin Magazine, The Quantum Issue, and was shared in advance as a preview of the issue.