ARK’s Valente more optimistic Bitcoin beats Q Day

Lorenzo Valente, ARK Invest’s Director of Research for Digital Assets, said in mid-October 2026 that he is more optimistic than he was a year earlier that Bitcoin will deploy a quantum fix before Q Day, according to Cryptobriefing. Q Day is the hypothetical point at which a quantum machine becomes powerful enough to break the cryptography protecting Bitcoin addresses.

Valente’s shift tracks ARK’s white paper with Unchained, published on March 12, 2026, which lays out five stages of quantum risk to Bitcoin and argues the threat builds gradually rather than arriving overnight.

Key facts

• Valente’s more optimistic stance, stated in mid-October 2026, is a change from his view in mid-2025.
• As of October 11, 2026, about 7.1 million BTC, or roughly 35% of circulating supply, sits in addresses with exposed public keys.
• ARK’s white paper with Unchained was published on March 12, 2026 and lays out five stages of quantum risk.
• BIP-360, a draft proposal for new output types, aims to strengthen Bitcoin’s defenses against quantum threats.
• ARK Invest holds its five-year Bitcoin thesis despite a flat year, Valente told Bitcoinmagazine.

The numbers behind the worry

Bitcoin relies on elliptic-curve cryptography to prove ownership of coins. A public key works like a padlock anyone can see, while the private key is what opens it. Classical computers cannot work backward from the padlock to the key in any useful timeframe, but a powerful enough quantum computer running Shor’s algorithm potentially could.

Cryptobriefing reported that ARK’s research characterises much of the exposed supply as either regarded as lost or held in addresses that can still migrate to safer setups. Lost coins cannot be moved by their owners, while migratable coins can be shifted to quantum-resistant addresses once those exist. The research also notes that most Bitcoin addresses use hashed versions of public keys, which are considered resilient because the actual public key stays hidden until the coins are spent.

Why the hardware is not there yet

Today’s quantum computers operate in the Noisy Intermediate-Scale Quantum era, or NISQ, a period in which machines are error-prone and limited in scale. Cryptobriefing reported that current hardware lacks the capability to threaten Bitcoin’s 256-bit ECC, and that experts expect it could take years or even decades to cross that threshold.

Draft proposals for new output types are under consideration, including BIP-360. According to ARK’s analysis, the Bitcoin ecosystem has shown awareness of the problem and readiness to adopt defensive measures, with ongoing community discussions suggesting the work is active rather than ignored.

Why it matters

The roughly 35% of supply in exposed addresses is the part of the network most likely to need migrating to post-quantum signature schemes. Holders using older address formats or reusing addresses face the most concrete exposure, since those coins would need to move once quantum-resistant options exist. Valente’s more optimistic framing marks a contrast with his own position a year earlier, when the deployment path for quantum defenses looked less clear.

What to watch

Key items to track include whether BIP-360 advances beyond draft status, how quickly wallets and exchanges support any new output types, and whether quantum hardware makes leaps beyond the NISQ era. Separately, Bitcoinmagazine reported that ARK continues to evaluate Bitcoin on a five-year horizon even as the asset has been flat to down this year.

This article is not financial advice. Cryptocurrency markets are volatile and uncertain, and readers should do their own research before making investment decisions.

Disclaimer: This article is for information only and is not investment, financial or trading advice. Cryptocurrency prices are highly volatile. Always do your own research.

Sources: Crypto Briefing, Bitcoinmagazine