Bitcoin's On-Chain Activity Hits a 2026 High as Coldcard Fallout Widens
Roughly 890,000 BTC moved on-chain over the past week — the highest active supply reading of 2026 — as the Coldcard hardware wallet attack pushes users to rotate custody setups en masse.
BY DEREK CHU5 MIN READ
Bitcoin on-chain activity reached a 2026 high as hardware-wallet users reassessed and rotated custody arrangements.
A 2026 high in coins on the move
Research firm K33 says bitcoin's seven-day active supply — the share of coins that changed hands on-chain — climbed to roughly 890,000 BTC, the highest weekly reading of 2026. Head of Research Vetle Lunde ties the acceleration directly to the Coldcard hardware wallet attack, which exploited a firmware bug that generated insufficient randomness during device setup. That flaw made some devices' seed phrases predictable enough for attackers to rebuild private keys and remotely drain funds, ultimately pulling roughly 1,596 BTC from about 7,300 exposed addresses.
Wallets are moving, not just whales
The reaction has been broad, not concentrated among large holders. On-chain analytics firm Santiment counted 2.27 million new wallets and 751,000 active wallets over the same week — the strongest activity reading in ten months. That pattern fits what security researchers see after any high-profile custody scare: affected and unaffected users alike move funds, spin up fresh wallets, and rebuild multisig setups rather than trust a device that might share the flaw. It doesn't mean coins are being sold — a transfer into cold storage looks identical on-chain to a transfer toward an exchange until the destination address is identified.
WHY IT MATTERS
K33 notes that spikes in active supply have historically shown up near both local market tops and local bottoms — the reading flags stress in the system, not a direction. What it does confirm is that a single firmware bug in one hardware wallet brand can move measurable amounts of the entire network's activity.
What to watch next
1.Whether active supply stays elevated into next week or reverts, which would suggest a one-time custody scare rather than a lasting shift in behavior.
2.Whether other hardware wallet makers disclose similar random-number-generation issues in their own audits.
3.Whether ETF flow data over the same window shows institutions reacting to the same custody concerns as retail wallets.
Frequently asked questions
What does "active supply" mean?
The share of the bitcoin supply that moved on-chain over a given window, usually seven days. It counts coins changing hands, not new coins entering circulation.
What caused the Coldcard attack?
A firmware bug generated insufficient randomness during wallet setup on certain Coldcard devices, making seed phrases predictable enough for attackers to rebuild private keys and drain funds remotely.
Does high on-chain activity predict where price goes next?
Not directionally. K33's research notes that spikes in active supply have historically shown up near both local market tops and local bottoms, so the reading flags stress, not a direction.
SOURCES & DATA
The Block — K33 on-chain activity report, August 2026 ↗
Santiment — wallet growth data, August 2026 ↗
Education, not financial advice. See our editorial process and corrections policy.
Derek Chu
Bitcoin Almanack's editorial byline for on-chain data, holder behavior, exchange flows, network activity, and technical market structure.
Sources, standards & corrections
Sources are linked inline. Read our editorial information, AI disclosure and corrections policy, or report an error.
Sources are linked inline. Read our editorial information, AI disclosure and corrections policy, or report an error.