Bitcoin Magazine said 6,900,573 BTC were cryptographically exposed to quantum risk at Bitcoin block 950,000, equal to 34.45% of circulating supply. The publication said that headline figure should not be read as the amount of bitcoin likely to be lost in a quantum event.
Its analysis said practical risk depends on whether the owner can respond, whether the entity remains operational, whether the balance is large enough to justify the cost of an attack, and how quickly funds can be migrated. On that basis, the report described the real exposure profile as narrower, more concentrated, and more dormant than the raw figure suggests.
Exposure snapshot at block 950,000
The raw total came to 6,900,573 BTC, or 34.45% of circulating supply, spanning 16,047,454 groups and 102,347,011 UTXOs, with an estimated migration time of about 140.99 days.
The active exposure filter for balances of at least 1 BTC and a five-year threshold contained 3,331,639 BTC, or 16.63% of supply and 48.28% of exposed supply. That bucket covered 46,163 groups and 4,906,508 UTXOs, with an estimated migration time of about 9.37 days.
For never-spent and inactive balances of at least 1 BTC, exposed supply was 3,413,767 BTC, or 17.04% of supply and 49.47% of exposed supply, across 113,627 groups and 2,669,847 UTXOs. The migration estimate there was about 5.29 days.
After removing known entities while keeping coins attributed to Satoshi, exposed supply fell to 2,277,978 BTC, equal to 11.37% of supply and 33.01% of exposed supply. That subset covered 73,658 groups and 1,096,018 UTXOs, with an estimated migration time of about 2.56 days.
At higher balance thresholds, the target set shrank again. Under the same filter, the >=10 BTC view contained 2,187,481 BTC, or 10.92% of supply and 31.70% of exposed supply, across 39,897 groups and 365,830 UTXOs, with an estimated migration time of about 23.33 hours. At >=100 BTC, the set dropped to 351,654 BTC, or 1.76% of supply and 5.10% of exposed supply, across 675 groups and 33,573 UTXOs, with an estimated migration time of about 2.17 hours.
Why the headline number does not equal likely economic loss
The report said the raw figure overstates practical theft risk because exposure in this context is defined as a cryptographic condition: a public key has appeared on-chain. That is the starting point, it said, but not the same thing as economic loss risk.
A live exchange wallet, an institutional multisig, a dormant early address, and an abandoned key can all be cryptographically exposed while having very different abilities to migrate funds. In other words, the same on-chain exposure does not produce the same real-world attack surface.
Active entities make up a large share, but they are also the most likely to move
The active >=1 BTC filter captured 3,331,639 BTC, or 48.28% of all exposed supply. Bitcoin Magazine said that is still a large amount of bitcoin, but it is concentrated in 46,163 groups rather than scattered across millions of unmanaged holders.
The largest visible active exposures include exchanges, brokers, custodial multisig operators, stablecoin infrastructure, and mining-related wallets. According to the article, those entities are among the most likely to monitor quantum developments, coordinate wallet rotations, and migrate before a practical attack window opens.
The piece said that does not make the exposure irrelevant. It framed the issue as one of coordination and execution risk, while drawing a distinction from lost-key risk: active custodial and exchange balances are generally the coins most likely to move first in a credible threat scenario.
The longer-term problem sits with dormant and non-responsive coins
The report identified dormant and non-responsive exposure as the core long-term problem. If active entities are excluded and the view is narrowed to never-spent or inactive balances of at least 1 BTC, exposed supply comes to 3,413,767 BTC.
After removing known operational entities but keeping Satoshi-attributed coins, the remaining exposed supply falls to 2,277,978 BTC across 73,658 groups and 1,096,018 UTXOs. The article described that 2.28 million BTC segment as the cleanest approximation in the dataset of the harder-to-mitigate exposure surface, including early holders, inactive self-custody, old address reuse, dormant P2PK outputs, and coins that may be lost or otherwise unable to respond.
That, the analysis said, is where practical quantum risk is most persistent.
Attack economics narrow the viable target list
Even a capable quantum attacker would still face operating costs, throughput limits, opportunity costs, transaction fees, and operational risk, the article said. For that reason, the rational target set is unlikely to include every exposed key and would more likely begin with the highest-value exposed balances.
The balance-threshold exercise showed how quickly the addressable attack surface compresses. After known entities are removed and only dormant or never-spent balances remain, the >=10 BTC view still holds 2,187,481 BTC but only 39,897 groups and 365,830 UTXOs. At >=100 BTC, the target set falls to 351,654 BTC across just 675 groups and 33,573 UTXOs.
Script-type breakdown shifts as thresholds rise
The script-type section was filtered to only show never-spent and inactive balances, with known operational entities removed and Satoshi coins retained unless the balance threshold excluded them.
At >=1 BTC, the script-type totals were:
- P2PK: 1,715,778 BTC
- P2PKH: 408,789 BTC
- P2SH: 43,444 BTC
- P2WPKH: 8,696 BTC
- P2WSH: 2,938 BTC
- P2TR: 98,327 BTC
At >=10 BTC, the totals were:
- P2PK: 1,715,539 BTC
- P2PKH: 356,368 BTC
- P2SH: 34,225 BTC
- P2WPKH: 5,271 BTC
- P2WSH: 2,886 BTC
- P2TR: 73,193 BTC
At >=100 BTC, the totals were:
- P2PK: 10,246 BTC
- P2PKH: 273,865 BTC
- P2SH: 21,113 BTC
- P2WPKH: 2,194 BTC
- P2WSH: 2,750 BTC
- P2TR: 41,486 BTC
The article said P2PK dominates dormant exposure at lower thresholds because early P2PK outputs are exposed by construction and are mostly inactive. P2PKH becomes the leading category in the >=100 BTC view after Satoshi-era 50 BTC outputs drop out. P2SH falls sharply once known operational entities are removed, leaving a relatively small dormant script-hash segment. P2WPKH stays low in the dormant non-entity view, which the report said is consistent with more modern wallet behavior and activity. P2WSH is very small after entity removal, while broader P2WSH exposure is likely institutional and active. P2TR is always exposed at the key level, but the high-value dormant non-entity subset remains limited.
The report added that displayed totals may differ by a few BTC from KPI totals because of dashboard rounding at the script-type level.
The threshold crossover does not mean P2PK risk disappears
Bitcoin Magazine said the apparent crossover from P2PK dominance at the >=10 BTC threshold to P2PKH dominance at the >=100 BTC threshold should not be read as P2PK risk fading away.
It called the shift mainly a filter artifact. In the dataset, Satoshi-attributed P2PK outputs are 50 BTC per key, so they are included at >=10 BTC and excluded once the pubkey balance threshold rises above 50 BTC. That exclusion causes the P2PK bucket to collapse from roughly 1.716 million BTC to about 10,000 BTC in the >=100 BTC view.
Bottom line from the snapshot
The publication’s main conclusion was that Bitcoin has a large cryptographic exposure surface but a much narrower practical one.
Active known entities account for a major share of exposed supply, yet they are also the participants most likely to migrate quickly. The more persistent risk is concentrated in dormant, non-responsive, and possibly lost coins.
Once known entities and low-value targets are filtered out, the economically attractive set becomes very small: 351,654 BTC across 675 groups at the >=100 BTC threshold. On that reading, quantum exposure is better understood as a concentrated dormant-coin problem, not a uniform risk across all exposed bitcoin.
The data source cited was a Bitcoin Quantum Exposure Dashboard snapshot at block 950,000. The article said the analysis assumes a separate dashboard methodology PDF supplied to the editor. Bitcoin Magazine said the piece appears in the latest print edition, The Quantum Issue, and was being shared online as an early look at ideas explored in the full issue. The story was written by Wicked.
