Over $100 million in Bitcoin was stolen across three separate attack waves targeting Coldcard hardware wallets, according to on-chain analysis by Galaxy Research. The firm confirmed 1,596 BTC stolen from approximately 7,300 addresses as of August 4, 2026, revising earlier loss estimates upward from $88.6 million.
Coldcard is one of the largest dedicated Bitcoin hardware wallets, marketed to users who manage their own private keys outside of exchange custody. The attacks represent a rare and significant breach of self-custody infrastructure, a practice promoted as safer than holding assets on centralized platforms following major exchange failures in recent years.
Galaxy's research shows the theft occurred in three distinct waves rather than a single event. The breadth of affected addresses, 7,300 wallets, spans a wide cohort of device holders rather than a single poorly secured user or a narrow technical flaw.
The incident arrives as institutional adoption of Bitcoin has accelerated through spot exchange-traded funds and self-custody mandates from some large firms. Hardware wallets are marketed to wealth managers and high-net-worth individuals seeking to avoid exchange insurance gaps and regulatory uncertainty.
No public statement from Coldcard addressing the attack's cause or scope has been released as of early August. Industry commentary from custodians and wallet firms typically follows such breaches within days as companies distance themselves from affected products or frame their own security practices as distinct.
The $100 million figure represents the largest confirmed hardware wallet attack loss in Bitcoin's history, surpassing earlier incidents at smaller scale. If the three waves indicate ongoing vulnerability rather than a closed exploit window, further losses could accumulate as additional users discover compromised wallets in the coming weeks.
