Bitcoin Quantum Exposure: 34.45% of Supply Vulnerable at Block 950,000

At block height 950,000, 6.9 million BTC (34.45% of the circulating supply) are cryptographically exposed. However, that headline figure should not be taken as the quantity at risk of theft in a quantum scenario. Practical threat depends on the owner's ability to react, whether the entity remains active, if the balance is large enough to make an attack worthwhile, and how fast coins can be moved. When these factors are considered, the actual risk profile is more concentrated and more dormant than the raw exposure number suggests.

• 6.90M BTC – raw exposed supply
• 34.45% – raw exposed share
• 3.33M BTC – active ≥1 BTC exposure
• 2.28M BTC – dormant unknown ≥1 BTC

Exposure Decomposition

• Raw total exposure: 6,900,573 BTC, 34.45% of supply, 100% raw exposure, 16,047,454 groups, 102,347,011 UTXOs, migration estimate ~140.99 days.
• Active, ≥1 BTC, 5-year threshold: 3,331,639 BTC, 16.63% of supply, 48.28% raw exposure, 46,163 groups, 4,906,508 UTXOs, migration estimate ~9.37 days.
• Never-spent + inactive, ≥1 BTC: 3,413,767 BTC, 17.04% of supply, 49.47% raw exposure, 113,627 groups, 2,669,847 UTXOs, migration estimate ~5.29 days.
• Never-spent + inactive, ≥1 BTC, known entities removed; Satoshi retained: 2,277,978 BTC, 11.37% of supply, 33.01% raw exposure, 73,658 groups, 1,096,018 UTXOs, migration estimate ~2.56 days.
• Same filter, ≥10 BTC: 2,187,481 BTC, 10.92% of supply, 31.70% raw exposure, 39,897 groups, 365,830 UTXOs, migration estimate ~23.33 hours.
• Same filter, ≥100 BTC: 351,654 BTC, 1.76% of supply, 5.10% raw exposure, 675 groups, 33,573 UTXOs, migration estimate ~2.17 hours.

These migration estimates are intended for relative comparison, not as predictions of actual coordination, fee pressure, or user actions.

Top-Level Analysis

1. The headline exposure figure overstates practical theft risk.

The raw figure of 6,900,573 BTC exposed is based solely on cryptographic condition — a public key having been revealed on-chain. While that is a valid starting point, it does not represent economic loss risk. Different entity types, such as exchange wallets, institutional multisig scripts, dormant early addresses, and abandoned keys, all have different migration capabilities despite being equally exposed.

2. Active and known-entity exposure is less concerning than raw exposure implies.

The active ≥1 BTC filter captures 3,331,639 BTC, or 48.28% of all exposed supply. This is a large amount of bitcoin, but it is concentrated in 46,163 groups rather than millions of unmanaged holders. The largest visible active exposures include operational entities such as exchanges, brokers, custodial multisig operators, stablecoin infrastructure, and mining-related wallets. These entities are among the most likely to monitor quantum developments, coordinate wallet rotations, and migrate before a practical attack window opens.

This does not make the exposure irrelevant. It creates coordination and execution risk. But it is meaningfully different from lost-key risk: active custodial and exchange balances are generally the coins most likely to move first in a credible threat scenario.

3. The core long-term problem is dormant and non-responsive exposure.

When active entities are removed and the view is narrowed to never-spent or inactive balances of at least 1 BTC, exposed supply is 3,413,767 BTC. After removing known operational entities while retaining Satoshi-attributed coins, the remaining exposed supply falls to 2,277,978 BTC across 73,658 groups and 1,096,018 UTXOs.

That 2.28M BTC segment is the cleanest approximation in this dataset of the harder-to-mitigate exposure surface: early holders, inactive self-custody, old address reuse, dormant P2PK outputs, and coins that may be lost or otherwise unable to respond. This is where the practical quantum risk is most persistent.

4. Quantum attack economics make the target set smaller still.

A capable quantum adversary would still face operating costs, limited throughput, opportunity costs, transaction fees, and operational risk. The rational target set is therefore unlikely to be every exposed key. It is more likely to start with the highest-value exposed balances.

Applying balance thresholds shows how quickly the practical attack surface compresses. With known entities removed and only dormant or never-spent balances included, the ≥10 BTC view still contains 2,187,481 BTC but only 39,897 groups and 365,830 UTXOs. At ≥100 BTC, the target set drops to 351,654 BTC across just 675 groups and 33,573 UTXOs.

Script-Type and Threshold Observations

The following data is filtered to include only never-spent and inactive balances, with known operational entities removed and Satoshi coins retained unless the balance threshold excludes them.

• P2PK: ≥1 BTC: 1,715,778 BTC; ≥10 BTC: 1,715,539 BTC; ≥100 BTC: 10,246 BTC. Observation: Dominates dormant exposure at lower thresholds because early P2PK outputs are exposed by construction and mostly inactive.
• P2PKH: ≥1 BTC: 408,789 BTC; ≥10 BTC: 356,368 BTC; ≥100 BTC: 273,865 BTC. Observation: Becomes dominant in the ≥100 BTC view after Satoshi-era 50 BTC outputs drop out.
• P2SH: ≥1 BTC: 43,444 BTC; ≥10 BTC: 34,225 BTC; ≥100 BTC: 21,113 BTC. Observation: Falls sharply once known operational entities are removed; remaining dormant script-hash exposure is relatively small.
• P2WPKH: ≥1 BTC: 8,696 BTC; ≥10 BTC: 5,271 BTC; ≥100 BTC: 2,194 BTC. Observation: Low in the non-entity dormant view, consistent with more modern wallet behavior and activity.
• P2WSH: ≥1 BTC: 2,938 BTC; ≥10 BTC: 2,886 BTC; ≥100 BTC: 2,750 BTC. Observation: Very small after known-entity removal; much broader P2WSH exposure is likely institutional and active.
• P2TR: ≥1 BTC: 98,327 BTC; ≥10 BTC: 73,193 BTC; ≥100 BTC: 41,486 BTC. Observation: Always exposed at the key level, but the high-value dormant non-entity subset remains limited.

Totals shown may vary slightly from KPI totals by a few bitcoins because of dashboard rounding at the script-type level.

Important threshold note

The apparent shift from P2PK dominance at the ≥10 BTC threshold to P2PKH dominance at the ≥100 BTC threshold should not be taken as P2PK risk diminishing. It is mainly a filter artifact: Satoshi-attributed P2PK outputs in this dataset are 50 BTC per key, so they are included at ≥10 BTC but excluded when the pubkey balance threshold goes above 50 BTC. That exclusion reduces the P2PK bucket from about 1.716 million BTC to approximately 10,000 BTC in the ≥100 BTC view.

Bottom Line

The key takeaway from the block-950,000 snapshot is that Bitcoin has a large cryptographic exposure surface but a much narrower practical exposure surface. Active known entities account for a major portion of exposed supply, and they are also the most likely to migrate quickly. The more persistent risk lies in dormant, non-responsive, and potentially lost coins. After removing known entities and low-value targets, the economically attractive set of targets becomes very small: 351,654 BTC across 675 groups at the ≥100 BTC threshold. Consequently, quantum exposure should be viewed as a concentrated dormant-coin problem rather than a uniform risk across all exposed bitcoin.

Data comes from the Bitcoin Quantum Exposure Dashboard snapshot at block 950,000. The analysis assumes the dashboard methodology PDF provided separately to the editor.