The Quantum Issue: Bitcoin Quantum Exposure At Block 950,000

Migration estimates are useful for relative sizing, not as forecasts of real-world coordination, fee pressure, or user behavior.

Bitcoin Magazine

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Oct 7, 2026 at 4:46 PM UTC · 5 min de leitura

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At block 950,000, 6.90 million BTC are cryptographically exposed, equal to 34.45% of circulating supply. That headline number should not be read as the amount of bitcoin likely to be lost in a quantum event. Practical risk depends on whether the owner can respond, whether the entity is operationally active, whether the balance is large enough to justify the cost of attacking, and how quickly funds can be migrated. Considering those dimensions, the risk profile is narrower, more concentrated, and more dormant than the raw exposure figure implies.

6.90M BTC Raw exposed supply

3.33M BTC Active >=1 BTC exposure

2.28M BTC Dormant unknown >=1 BTC

Exposure Decomposition

View	Exposed BTC	% Supply	% Raw Exposure	Groups	UTXOs	Migration Est.
Raw total exposure	6,900,573	34.45%	100.00%	16,047,454	102,347,011	~140.99 days
Active, >=1 BTC, 5-year threshold	3,331,639	16.63%	48.28%	46,163	4,906,508	~9.37 days
Never-spent + inactive, >=1 BTC	3,413,767	17.04%	49.47%	113,627	2,669,847	~5.29 days
Never-spent + inactive, >=1 BTC, known entities removed; Satoshi retained	2,277,978	11.37%	33.01%	73,658	1,096,018	~2.56 days
Same filter, >=10 BTC	2,187,481	10.92%	31.70%	39,897	365,830	~23.33 hrs
Same filter, >=100 BTC	351,654	1.76%	5.10%	675	33,573	~2.17 hrs

Migration estimates are useful for relative sizing, not as forecasts of real-world coordination, fee pressure, or user behavior.

Bitcoin Quantum Exposure Analysis Brief – Block 950,000 Page 1

Top-Level Analysis

1. The headline exposure figure overstates practical theft risk.

The raw view shows 6,900,573 BTC exposed, but it intentionally treats exposure as a cryptographic condition: a public key has appeared on-chain. That is the right starting point, but it is not the same 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.

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.

Market Context

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