More than 30% of all issued Bitcoin sits in addresses that could one day be broken by a quantum computer, according to new data from analytics firm Glassnode. The report, published this week, puts the combined quantum-exposed supply at 6.04 million BTC, split between two categories: an older structural exposure from legacy script types, and a far larger operational exposure caused by address reuse and partial spending. The operational bucket alone — 4.12 million BTC — is more than double the structural one.
Where the exposure lives
Exchanges are the biggest single source of operational risk. Glassnode estimates that roughly 1.66 million BTC held on trading platforms falls into the operational bucket, about 40% of the total. The split varies sharply by exchange. Coinbase holds only about 5% of its balances in exposed outputs; Binance sits at roughly 85%; Bitfinex is close to 100%. Asset manager WisdomTree appears fully exposed on-chain, while Grayscale keeps about half its supply in high-risk outputs. Sovereign wallets belonging to the United States, the United Kingdom, and El Salvador show zero exposure.
Why operational exposure is the real problem
The structural category covers older scripts — Pay-to-Public-Key, bare multisig, and Pay-to-Taproot outputs — where public keys appear on-chain by default. That's been known for years. What's new is the finding that operational exposure (affecting P2PKH and P2WPKH addresses) is 2.1 times larger. Glassnode attributes the scale to key- and address-management failures: reusing addresses, partially spending UTXOs, and poor custodial hygiene. “Much of the operational bucket can shrink today through address rotation and avoided reuse without consensus changes,” the firm notes in its analysis.
What can be done now
Bitcoin Improvement Proposal 360 would harden Taproot against quantum exposure if activated, but that requires community consensus. In the meantime, individual holders and exchanges can move funds to fresh addresses — a step that would instantly remove those coins from the operational risk pool. The data shows the proportion of exchange-held BTC that is operationally safe has drifted from roughly 55% in 2018 to about 45% today, suggesting the industry has been moving in the wrong direction. Whether the major exchanges decide to rotate their wallets — and how quickly — will determine how much of that 4.12 million BTC gets protected before the quantum threat becomes practical.
